TIDBITS OF INFO- GOLD RELATED

rehab · TIDBITS OF INFO- GOLD RELATED

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COLUMN ONE
Gold or Just a Fever?
A 1930s prospector insisted that a Mojave peak hid an underground river flowing with the ore. Some are chasing that dream today.
By Ashley Powers, Times Staff Writer
September 11, 2006

KOKOWEEF PEAK, Calif. — The earthen ridge rises 6,038 feet from scrub brush and sand, an unspectacular summit were it not for the legend: a river underneath, overflowing with gold.

At least since the 1930s, leather-skinned prospectors have chased the tale to a mining shantytown at the base of the peak, on the edge of Mojave National Preserve, where the cheeriest structure is a pink shed that bears the warning "Keep Out."

Today a hard-bitten crew of treasure hunters huddles in plywood homes, enduring icy winters and roasting summers. Their big-city neighbor is an apt one: Las Vegas, about 75 miles away, which also welcomes dreamers happy to risk savings and sanity.

Kokoweef — a name believed to stem from Southern Paiute words meaning "gopher snake canyon" — lures its own kind of gamblers, though these days barely enough for a hand of seven-card stud: a military surplus merchant, a cocktail waitress, a retired construction manager and a few others.

Their quest, however, comes with this caveat: It consumed Earl Dorr, the brusque miner who fathered the legend — and who may have concocted it for his own nefarious ends.

The bleak sands of the Mojave conceal a bounty of treasure. Native tribes pocketed agate and turquoise long before Nevada's silver rush in the 1860s, which sent fortune-hungry miners scrambling into the Providence, Mescal and Clark ranges.

Tent cities sprouted in the sand. Some matured to communities of shelters cobbled from rocks and juniper poles — with most towns building the requisite general store and saloon and sometimes a brothel.

Ivanpah, among the largest on the California-Nevada border, boomed to several hundred residents, but it and most smaller outposts went bust when the silver, copper or tin markets crashed.

The mining rush slowed to a trickle by the 1930s. Into this desolate landscape wandered Dorr, a prospector with blue eyes, a shoulder-holstered gun and "immaculate table manners," said his nephew Ray Dorr, 78, a retired contractor in Cañon City, Colo., who is writing a book about Kokoweef.

Earl Dorr, born in the 1880s to wealthy Colorado cattle ranchers, traveled the Southwest in search of a mine that would make him rich. He would visit Ray's father in Pasadena, striding to the door in a Stetson hat with a sack of penny candy for the kids, whom he entranced with tall tales.

Along the way, Dorr either "discovered the richest gold deposit in the United States … or he was the most imaginative liar in the state of California," his nephew wrote in a 1967 article for Argosy magazine.

Dorr told The Times in 1936 that he came across Kokoweef when he checked into a Death Valley tale that three men who stumbled upon the golden river had deposited $57,000 in a Needles, Calif., bank.

Dorr told his nephew a different version: that he had befriended three Indian brothers who had discovered a river thick with ore in a Kokoweef cavern. After one brother plummeted to his death in the cavern, the other two refused to return to the mountain and told Dorr the tale.

The mountain, near the Ivanpah range, has three sizable, nearly vertical caves with limestone chambers: Kokoweef, Crystal and Quién Sabe — Spanish for "who knows." In 1934, Dorr produced a sworn statement that said he and an engineer, whom he identified only as Mr. Morton, descended several thousand feet into chambers he called "one of the marvels of the world."

On the floor of a half-mile-deep canyon, Dorr said, he came across a river, about 300 feet wide, that rose and fell as if it were breathing. The water receded to reveal black sand. Dorr said he panned it and found gold. Lots of it.

Dorr told The Times that upon returning to the surface, he dynamited the cavern's entrance to keep others from plundering his bounty while he filed a mining claim.

Within the next decade or so, cave explorers from Pasadena, curious about the tale, shimmied into a cavern and found "D-O-R-R" seared onto a wall.

Dorr's statement was published in the California Mining Journal in 1940, and it has been the source of endless speculation ever since. Why would he write up such a strike when he went to such lengths to hide it? Yet, if he were telling the truth, weren't untold riches just waiting to be rediscovered?

Larry Hahn opts for the latter.

In the 1980s, Hahn, who owns a military surplus store in Las Vegas, became the latest in a series of folks to entrance investors with Kokoweef. He is a partner in Explorations Inc., which has leased land from a company that owns 85 acres near the mountain and has mineral rights to 300 more and would share profits from any cache discovered.

Hahn, 68, said he had coaxed 300 to 500 investors to chip in for drilling, blasting and zapping the mountainside with electric current to pinpoint where to drill.

His newsletters promise gold like a televangelist promises salvation: "It only takes that one lucky hole that is connected to the big void to show us the way," one newsletter reads.

On a recent afternoon at base camp, Hahn said the search seemed as feasible as dredging for gold doubloons. "But in this day and age, we don't have buried treasure; all of it's been found. This is the last frontier," he said.

Only the most devout trundle up Zinc Mine Road, a tire-busting path that zigzags past boulders and Joshua trees about a mile from where long-extinct coelurosaurs imprinted what might be the state's only dinosaur tracks. The occasional hand-lettered sign reassures that the path peters out at "Kokoweef" — a graveyard of sagging buildings and rusting mining equipment.

At the plywood-and-pallet home that he built, one wall plastered with his great-grandfather's claim certificates for a gold mine, Randy Stenberg, 59, a retired construction manager, tends to his dreams.

His wife, Bernice, 50, a cocktail waitress at the MGM Grand casino in Las Vegas, had dismissed Larry Hahn as a huckster who had blinded her husband with a fable. But nearly 15 years ago, the Stenbergs descended from their 13th-floor condo near the Las Vegas Country Club for a tour of a tunnel that miners had chiseled.

Hahn's pitch was simple: "If you hit it, you're talking about the biggest thing that ever happened."

The couple threw in about $1,000, inspecting their investment on weekends and scraping rock and debris from the mine. It wasn't until four or so years ago that they settled at base camp, where electricity churns from solar panels and, for about two hours a day, a generator.

Residents fetch water from a pool that seeps from rocks in the Mescal range. One neighbor, a retired factory worker in her 70s, plans to spend the rest of her days staring at the spindly Joshua trees that hem in the hodgepodge of structures.

Randy Stenberg passes time slogging through one 1,200-foot tunnel into Kokoweef Peak and gazing at the zinc mine's ballroom ceilings and relics of miners past, such as a leather jacket and a V8 juice can ossified in dust.

"Gambling's for fools," he said recently from a frontyard whose sole decoration was a pink flamingo. "I don't consider this gambling — looking for something that's possibly there. You'd go down in history with it."

The miners under Hahn's direction long ago abandoned the sometimes dodgy work of blasting Kokoweef with dynamite. They instead poke at the mountain with more inventive tools, including microphones that help measure sound from small explosions to see if it pings off ore.

The latest novelty is a drill. It is as tall as a two-story home and topped with a skull-and-crossbones pirate flag. Several miles from base camp, the machine labors six to eight hours a day, burrowing deep into the dirt. The rationale: When the drill hits nothing, it will have found the cavern, or the path to it.

Geologists scoff at the legend, saying Kokoweef Peak could never harbor such a deep cave or a raging underground river. The desert is too dry. The amount of gold said to be packed into the riverbed — at least 50 tons, by Dorr's estimate — is too great. Not even Gold Rush miners in the Sierra Nevada foothills unearthed such a cache.

Paleontologists working with the San Bernardino County Museum dug at Kokoweef Peak in the 1970s, recovering more than 200,000 animal remains, including fish bones. Birds had carried the fish from the Colorado River, scientists determined, but some miners took them as evidence that Dorr's golden river — and its mother lode — existed.

"If it would have been there, this guy would have mined it all and be rich as can be," said Ted Weasma, a Mojave National Preserve geologist.

Dorr's nephew and at least one prospector who has lived at Kokoweef are convinced that Dorr pulled a bait-and-switch on his fellow miners — signing the sworn statement to attract investors without giving up the gold's location or even guaranteeing that he had found it.

The prospector may not have shimmied through a small hole near Kokoweef's Crystal Cave but elsewhere in the Mojave, said Ralph Lewis, 54, an electrical apprentice who has distanced himself from Hahn's operation and is writing a book about the legend.

As evidence of such a subterfuge, both men point to a mining shack Dorr built, about 8 feet wide with a double bunk — not in the Ivanpah Mountains, but in the nearby Mescal range. Lewis, who lived in Kokoweef off and on for a quarter-century, is convinced that this is the so-called Dorr Peak, depicted on rudimentary maps as providing a second path to the underground river.

Dorr's lifelong search for another route to his treasure gnawed at him, especially after the legend piqued a mining company's interest in the 1930s. Its workers discovered zinc and gave up on the gold. Dorr claimed that the zinc mining had destroyed routes to his horde.

"I got the wrong class of men, all talk — the class we old desert prospectors call drugstore miners. It was too big for them — too big a thing," Dorr told author Howard D. Clark after the firm ditched its plans to find gold.

"I stuck as long as I could, until I was eating cooked watercress, chipmunk soup and sagebrush tea. I starved out and had a light stroke, which put me on my back for a whole year," he said.

After deserting the shack in the Mescals, he worked as a shipyard welder, then as a watchman at an Adelanto tungsten mine. The prospector died in the 1950s, his pan empty.

ashley.powers@latimes.com

(INFOBOX BELOW)

Treasure map?

Miners have flocked to Kokoweef Peak, a remote 6,038-foot mountain in the Mojave Desert, since at least the 1930's, when a man named Earl Dorr produced a sworn statement that he had discovered gold in a river underneath it.

Source: "Adventure Is Underground" by William R. Halliday

(END TEXT OF INFOBOX)

rehab · AMALGAMATION TO RECOVER FINE GOLD EMJ 8 4 1928

Recovery of Fine Gold by Amalgamation

THE frequency of cases of poor recovery of fine gold by the amalgamation process has led the U. S. Bureau of Mines to publish an information circular on the subject. (No. 6,081, by Edmund S. Leaver). Experience has shown that often error has been made because the true gold content of a particular sample or deposit was not known. Fire assays of representative samples give accurate results and should be considered final in determining the gold content.

The best method to use for recovering gold depends on the form of its occurrence in the material to be handled. An experienced operator can obtain a good idea of the amount of free gold and can tell something as to the fineness of it by careful panning. The sulphides should be separated and cleaned from the free gold and gangue, and then weighed and assayed. If the sulphide carries gold, it is probable that pad of the gold in the slimed portion is locked up with sulphides and will not amalgamate. It is advisable, if practicable, to have an expert make a microscopic examination and report on the minerals present and how they are associated in the gangue. Such an examination is needed by the examining mining engineer or metallurgist before he can recommend methods of recovery.

The fine gold lost in the usual amalgamation processes is often called “float gold.” Most of this gold is probably in the form of thin laminated, flattened grains, or scales, and its loss is caused by non-contact with the mercury. A thinner pulp, provided by the introduction of swinging amalgamated plates as obstructions in the pulp flow, and the stirring action caused by more frequent drops onto the different sections of the amalgamation plates, have improved the recovery of such gold. Fine gold is readily recoverable by good contact with the amalgamation plates and should not be confused with the gold included in fine sulphides or in other non-amalgamating forms.

“Rusty gold” is a term that has been adopted to designate gold which, though apparently free, does not readily amalgamate. It is known that a thin film of sulphur, oxide of iron, silica, grease, or other substances may cover the surface of the gold particle and prevent amalgamation. The film is usually attacked by grinding or some form of abrasion and by the use of alkalies or other chemicals to dissolve the grease.

Fine gold contained in pyrite does not readily unite with mercury. This gold is mostly recovered with the pyrite concentrate or leached by cyanidation. Tellurides do not give up the contained gold to direct amalgamation. The roasting of pyrite and tellurides improves the condition for amalgamating the gold, but does not insure a high recovery.

Silver-plated copper plates are generally used to recover the free gold from ore by amalgamation processes. For best results the plates must be kept as clean as possible. Mercury is worked into the surface of the plates until there is exposed a bright pasty amalgam that readily retains the gold as the ore pulp flows over the surface. To affect amalgamation each particle of gold must come into contact with the mercury. Good amalgamation conditions are easily reversed by the careless introduction of oils and grease. Soluble sulphides in the ore will darken the mercury and lower the gold recovery. Arsenic and antimony are particularly harmful, as are many of the base metals.

Engineering and Mining Journal— Vol.126, No.16 8 4 1928

rehab · ENZLIN-EKLUND PLATINUM & GOLD AMALGAMATION EMJ 10 20 192

The Enzlin-Eklund Platinum-Gold Amalgamation Process

FOR some time metallurgical circles in the Transvaal have exhibited a keen interest in the evolution of a new process for the amalgamation of gold and platinum which has been patented by two local metallurgists, Messrs. Enzlin and Eklund. The invention is applicable to sulphide and oxide platinum ores and to both free-milling and refractory gold ores. It permits the recovery of the metals directly from their ores without preliminary concentration, though it is also applicable to concentrates. According to a description of the invention, the ground ore or other material containing the precious metal is brought into contact with zinc amalgam in the presence of an activator, the precious metal being thereby amalgamated and retained by the amalgam. The amalgam is preferably applied to an iron or nickel surface.

The inventors’ investigations indicate that highly complicated reactions occur as a result of the contacting of the activator, the ore constituents, and the elements of the amalgam, and that these reactions differ with different activators and different ores; but in a broad sense the function of the activator appears to be (a) that of rendering the surface of the metallic or mineral particles bright by removing any deterrent coating, such as oxide, sulphide, arsenic, antimony, or absorbed oxygen, and (b) in treatment of the platinum group metals or minerals, that of preventing oxidation or absorption of oxygen and so promoting the covering or wetting of the particles by amalgam.

The activators which have been found most generally useful are an aqueous solution of mercuric hydrochloride, zinc chloride, hydrochloric acid, and free chlorine. The mercuric hydrochloride may be mercuric tn-chloride (HHgCI3)1, mercuric tetrachloride, (H2HgCl4) or mercuric pentachloride (HHg2CI5) or any combination of them. Improved results are generally attained if an alkali chloride such as sodium chloride is present.

The preferred process consists in crushing the ore to about minus 200 mesh in solution that has already passed through the process and contains mercuric hydrochloride salts, zinc chloride, chlorine, and sodium chloride. A small quantity of hydrochloric acid is then added to the pulp and the acidified pulp is passed over an iron or nickel surface coated with zinc amalgam, which retains the precious metal. At the same time, the hydrochloric acid reacts with the zinc amalgam, producing a further quantity of mercuric and zinc salts, which goes into the solution.

After passing off the amalgamated surface the solid and liquid constituents of the pulp are separated by settling, and the solid constituent, containing some solution, is discarded. The clarified solution is then passed through an electrolytic cell wherein some of the zinc and mercury carried in solution are deposited in the cathode, the quantity thus deposited being approximately that dissolved when the pulp was passed over the amalgamated surface, thus keeping the strength of the solution constant and preventing the zinc and mercury salts from building up to an undue concentration. The metallic zinc and mercury so recovered may be used for redressing the amalgamated surface.

A solution strength which has been found satisfactory consists of: Hydrochloric acid, 1 per cent by weight; zinc chloride, 0.25 per cent; chlorine, 0.025 per cent; mercuric hydrochloride, 0.005 per cent; and sodium chloride, 0.25 per cent. These proportions may be varied considerably. For gold ores the amount of acid may be such that the solution is approaching neutrality when it leaves the amalgamated surfaces, but for all platinum ores a greater amount of acid should be used.

It is found to he desirable to have a relatively long period of contact between the ore and the activator solution before the pulp is passed over the amalgam. With gold ores, five minutes is generally a suitable time for the preliminary mixing of the ore with the activator solution, whereas with platinum ores from thirty minutes to one hour is required. After this mixing, the actual amalgamation takes place rapidly, in a period ranging from fifteen to sixty seconds.

With ores containing metallic gold or platinum, the amalgamation takes place on the metal itself, after its surface has been cleared by the activator solution. In an ore containing combined platinum, for example sperrylite, the action appears to be decomposition of the surface of the mineral particle by the activator solution, platinum going into the solution. This is precipitated by the zinc present, forming zinc platinum amalgam, so that the particle is wetted by the amalgam and is absorbed therein.

Colloids tend to prevent the amalgamation of the metallic or metalliferous particles, however clean and bright the metallic surfaces may be. This difficulty is overcome by the presence of the zinc chloride, acetic acid also being added sometimes, as when hydrated ferric oxide is present, to prevent the formation of a film of hydroxide gel in the interstices of the amalgam.

1 The more commonly expressed formula for these compounds is HgCl,.NHCI. They may be made by decomposing mercurous chloride in boiling hydrochloric acid.—EDITOR.

October 20, 1928—Engineering and Mining Journal 621

rehab · GILBERT GOLD CONCENTRATOR DESCRIPTION TMJ 3 30 1929

THE MINING JOURNAL

Gilbert Concentrator Manufactured in Phoenix—The Old Town Mining and Development Company, 15 N. Second Avenue, Phoenix, Arizona, has secured the exclusive manufacturing rights for the new machine, known as the Gilbert Concentrator.

This machine, Patent No. 1477053, has a capacity of 150 yards per eight hours, and requires only a 3/4 -inch stream of water.

The material is carried from the receiving hopper by elevator to a trommel washer and grader, from there by chute to Table No. 1, where all values and concentrates are graded out. These then pass by chute to Table No. 2, which is provided with separate pan with dividers and ripples and so built that the pans may be quickly removed without disturbing the rest of the machine. Here all values except black sand are saved.

This black said, it has been found, may be divided into two classes; the magnetic sand to which the flour gold clings, and a heavier non-magnetic sand, which analysis proves to be tungsten sand. Both classes are then caught by Table No. 3 and the values in the latter in some cases pay for the operation of the machine.

The entire machine is operated by a 4 1/2-horsepower engine, handled by one man. J. C. Mason, secretary-treasurer of the Old Town Mining and Development Company, is in charge at the company’s offices in Phoenix.

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rehab · HOW FIND TO GRIND GOLD ORE THE MINING JOURNAL 6 30 1931

Effect of Excessive Grinding Prior to Wet Chemical Treatment

QUERY was recently made as to how fine a gold ore should be ground to insure maximum recovery by cyanidation. The question was unanswerable without ample data, but these were not forthcoming.

The impression was held that the highest recovery inevitably followed comminution to the ultimate limit, and it was difficult to undermine this deep-seated conviction. A point invariably overlooked is that excessive fine grinding results in the intensification of surface-tension influences, which unquestionably exert a powerful effect on the solution with which the ore particles are surrounded.

The area of solid thus exposed is too vast to permit of computation. Complex and intense inter-phase reactions between solid and liquid are inevitable, and it is probable that many an unfavorable result in the cyanidation of a simple gold ore that has been finely ground may be attributed to this action.

To quote from an article published ten years ago:
“Absorption of metal by colloid particles plays an important part in the all-sliming process and may he cited as one reason at least for the non-recovery of all the extracted metal.

It is no longer possible, in the light of contemporary investigations, to speak definitely of dissolved or undissolved gold after cyanide treatment, when it is impossible to determine how much of the metal has been dissolved and absorbed, and how much has been untouched by’ the solvent.

Absorption and adsorption are phenomena that are largely influenced by the question of fineness of division; and this fact may serve to explain the reason for the comparatively high residual content after milling and fine grinding in a cyanide solution carrying valuable metal, or in which a proportion of the metal is immediately dissolved.”

The article in question also dealt with the opportunities offering for greater economies and the reduction of such hazards in the treatment of a gold ore. Recent developments and tendencies suggest that other parts of the article are worth repetition.

An example was quoted of research at a property where previous milling operations showed that 86 per cent of the gold could be concentrated in about 7 per cent of the tonnage. Tests on the 93 per cent remaining, constituting the tailing after amalgamation and concentration, showed that this could be reduced to 45 cents per ton by crude cyanide methods, and apparently without further grinding expense.

To a metallurgical onlooker, these results seemed to indicate in outline how a successful scheme of treatment might be formulated. The 45-cent residue, however, was considered discouraging! And further experiments on a sand of normal fineness for leaching purposes were apparently not considered.

Tests were made to see how much gold could be dissolved by an experimental agitation treatment. The results indicated that all was soluble, provided grinding was carried far enough. Laboratory extractions of 99.7 per cent were obtained with clean solutions; and as a result it was decided to grind and re-grind the 7 per cent of the concentratable material without separation from the 93 per cent of low-grade re, so that every particle of worthless rock and absorbent colloid should be thoroughly steeped in as rich a solution of gold as possible!

History has shown that results are not always as one would wish or as might be expected by those who disregard the complexity of a working cyanide solution and the adsorptive nature of any finely ground material. When all up-to-date refinements have been adopted, and residues are still high after such treatment, it is not uncommon practice to follow countercurrent decantation by filtration; and if the residues are stilt high, to re-pulp and refilter, and then to seek additional means of treating the tailing in an attempt to reduce gold content.

The application of remedial measures at the tailing end of the plant is seldom completely successful, especially when the trouble is due to a cause that demands something more than a repetition of normal treatment. Physiochemical advance ten years ago showed that the decomposition of an unstable solution and the removal of a constituent may be insured by bringing it in contact with a solid that had been subdivided to present an immense surface area. The greater the subdivision, the greater the surface action.

In every phase of cyanidation the hazard of residue loss may be minimized by limiting excessive comminution to a concentrated product or to a middling that has been impoverished of as much gold as possible. The practice of steeping finely divided but worthless gangue material in a rich solution of gold is almost certain to lead to an otherwise avoidable residue loss.

rehab · GEOPHYSICS IN GOLD MINING THE MINING JOURNAL 8 15 1931

for AUGUST 15, 1931

The Use of Geophysics in Gold Mining
By J. J. JAKOSKY, Technical Director, International Geophysics, Inc., Culver City, California.
White no geophysical method can be depended upon to locate gold directly, many
important applications of geophysics are being made in gold mining.

Introduction
The present cyclic economic conditions, resulting in a relatively higher value for gold, as compared with the prices of other metals, has given a stimulus to gold mining. A large majority of mining promotions and developments during the past six months (early part of 1931) have been gold properties. From the inquiries received by this company the effect of the present economic depression is shown in the type of information desired by prospective purchasers of properties and those vested with the responsibility of development. It is clearly evident that the “risk all, gain-all” attitude of mining is slowly but surely giving way to a more conservative and unquestionably more constructive mining procedure on the part of the public and the operator.
Our inquiries indicate that placer properties are receiving a somewhat greater interest than vein deposits. This may be due to the psychology of many business and professional men who are now investing in mining enterprises. The unfavorable condition of oils and stocks has brought many such investors into mining enterprises, and they naturally approve of that type of mining where their familiar business or manufacturing procedure can be more directly applied.
Placer mining, while not favored with the large strikes or bonanzas of vein and pocket deposits, is of a type where careful planning can oftentimes produce a satisfactory return on the investment. Placer mining, one of the oldest forms of mining, at present produces approximately 20 per cent of the world’s gold. A major portion of placer gold is derived from Tertiary or Quaternary placer deposits, with a small quantity coming from Cretaceous conglomerates in northern California and Oregon. The general conditions governing placer development allow much valuable information to be derived from geological and geophysical studies of the deposits. A brief review of placer formation is given in this paper in order to more clearly illustrate the application of the geological and geophysical work necessary in the development of such deposits.

The management of properties is making an increasing effort to use its development money as economically and effectively as possible. Expenditures are being made more cautiously and development programs planned to protect successive expenditures in the development of the property. The relatively low cost of geophysical work, coupled with the results now being obtained makes it a logical step in the exploration program before planning the development work. This paper illustrates various applications of geophysical work, as conducted by the staff of International Geophysics, and applied to the development of gold properties. In a brief way, the uses and limitations of geophysical work are discussed, as applied to the usual problems encountered in vein and placer mining for gold.

No Geophysical Method Detects Gold
No geophysical method can be depended upon to locate gold directly. For detection Gold, while an excellent electrical conductor, does not occur in nature in sufficient abundance to give the rocks or gravels in which it occurs an electrical conductivity different enough from the surrounding country rocks to indicate its presence by measurements made from the surface. For detection by the magnetic methods, gold is a paramagnetic or weak material and, because of the small percentage present in the rocks, does not produce a sufficient magnetic anomaly to render its detection by magnetic measurements made at the surface of the ground.

The direct location of gold by any known commercial geophysical method is so far unknown. Fortunately, however, a number of measurable and related conditions exist with gold occurrence, which makes the geophysical work an indirect, but reliable means for determining the location of gold-bearing veins and placer concentrations. All of these methods must, however, be applied after due consideration has been given the characteristics of the district, with proper correlation of the geological and geophysical data.

Because of the interdependence of factors governing geophysical work, there are no simple rules or criteria for conducting the fieldwork. The crew must be experienced personnel and provided with sufficient equipment to allow the application of such geophysical methods as it may be necessary to employ to obtain the desired data. There is no substitute for experience, modern equipment and a proper field procedure. Conditions that may be unfavorable in one case, may be desired in another case. Knowing the information desired from the geophysical work, each particular problem must be considered individually, with due regard to the geology of the district, ore occurrence and previous history of the district, topography, level of sub-surface water, information from present workings (shafts, drill-holes, trenches), etc., by the electrical methods.

Geophysics Applied to Vein Deposits
The applications and limitations of geophysical work applied to vein deposits can best be illustrated by examples from recent fieldwork.
In the Ellsworth mining district of Arizona gold values occur associated with pyrite. The pyrite, being a good electrical conductor and existing in considerable quantities, makes the vein material highly conductive. As a result, the electrical methods were readily employed for determining the presence, the depth, dip, strike and extensions of such pyritic veins, with the associated gold. Under these conditions the geophysical work is an excellent method of studying the sub-surface conditions, provided the geophysical data is properly interpreted in light of the geology.
In the same district also occur veins, which have been altered, and as a result we have a limiting case where geophysical work can not directly or indirectly locate the gold-bearing vein material. This property contains a well-defined, iron-stained, outcrop of veins, or gossans, which carry some gold. The amount of gold is, of course, far too small, as regards its volume and electrical effect, to make any measurable difference on the electrical properties of the vein. Preliminary measurements over the vein gave no important electrical differences. In other words, no detectable quantity of sulphides existed in the vein material. The valuable mineral content (gold) in the vein, was present and the electrical work was, therefore, unable to give any information as to the depth to which the vein material might extend, or its probable value with depth. Had the pyrite content of the vein not been completely leached, the geophysical work could have been depended upon to give the depth of the vein, and also to predict the probable value of the vein with depth. The history of the district shows that the gold content of the veins remain constant with depth.

Before geophysical work is applied to primary gold formations all possible information must be obtained of the general geological conditions existing in an area. If the previous history of the district, and the local conditions, indicate that sufficient sulphides exist with the gold, the geophysical work is conducted to locate the sulphide areas. In other words, geophysics is being used only for locating the sulphide zones, with which the previous history of the district indicates gold will be found. If, as shown by our second case, the sulphides have been removed, the modus-operandi of the geophysical work is gone for this particular problem.
The absence of sulphides, in another case, allowed the geophysical work to obtain the desired information whether the vein extended to depth. On this property a well-defined fracture vein, in which a quartz filling appeared to have a lenticular distribution outcropped for several hundred feet on the surface. The quartz was colored with iron and copper stains and an abundance of pyrite casts could be found. It was known from previous mining operations that the oxidized or leached zone did not exceed 150 feet, and it was necessary to ascertain whether the vein extended to depth. Resistivity measurements showed that no sulphide existed below 150 feet, which (with the supplementary geological studies) lead to the conclusion that the lens pinched out at that depth and the property was worthless. No further mining operations were recommended.

The presence, or absence of, sulphide zones are not always the important factor. This is well illustrated by a geophysical survey conducted in Inyo County, California. The gold on this property occurred as free gold, in quartz veins, which outcropped prominently at the higher elevations. The vein was worked to shallow depths along its surface outcrop. At the bottom of the hill the vein disappeared under fill. In order to properly plan larger scale operations it was necessary to learn if the vein extended for an appreciable distance under the fill material. The geophysical work readily showed the extent and location of the vein, thickness of fill material, and an important fault zone and other relevant data.
This type of problem is essentially a structural problem, inasmuch as the work is carried out to obtain details regarding sub-surface structure beneath the detritus or fill material, and no effort was made to locate the mineralization directly. The vein was located at a small fraction of the cost of any other method of exploration. After the geophysical work, only a few drill holes were necessary to determine the values of the vein, and to plan the development work.

Residual or Eluvial Gold Deposits
In areas where considerable surface erosion has taken place, there is a type of gold deposit intermediate between the original primary deposit and the placer. When the veins containing the primary gold are decomposed, a gradual concentration of the gold occurs in the loose detritus. The gold found in such deposits is usually rough and coarse, and of practically the same fineness as the gold in the primary vein. This gold is oftentimes washed or carried into cracks or seams in open formations. This condition is found in many localities in Nevada and Central California, where gold-bearing veins are found in schists.
In deposits of this type, simple geophysical work can be very advantageously employed to determine the depth to bedrock and thickness of fill or detrital material. This information is necessary in order to determine location and depth of drill-holes, test-pits or shafts for sampling, and the tonnage of the deposit.

Theory of Placer Deposit. (1)

The gold contained in a placer deposit was originally derived from the primary supply contained in lodes, veins, shear zones and certain intrusive rocks. As the rocks were decomposed by surface weathering we often have the formation of the residual or eluvial deposits previously described. Continued weathering and washing by water gradually transports the products, and at the same time classifies or separates the lighter and heavier materials, in much the same manner as the familiar classifiers and concentrating jigs used for ore recovery. The finer the state of sub-division and the lower the specific gravity of a material, the easier it can be transported by running water. The heavier and more weather resistant materials, on the other hand, are transported less easily by water, and where various materials are being carried along by water, the heavier materials will be deposited as the velocity decreases.
As a result of this action certain of the more resistant heavier materials are accumulated at places in the stream channel where the velocity decreases and conditions are favorable for their accumulation. The commercially valuable materials usually found in such deposits are gold, platinum, cassiterite (tin), monazite (containing thorium), and chromite, mixed with gangue materials consisting usually of quartz, magnetite, hematite, ilmenite, garnet, zircon and other more resistant rock materials. The lighter products of rock disintegration, such as clay, limonite, etc., are carried away in suspension by the water. Continued washing and later floods continue the classification. The gold and other heavier material gradually work to the bottom of the mass and are concentrated on the bedrock. During the flood and high-water periods the whole water-impregnated sand and gravel mass slowly moves downstream (2), allowing the finer gold particles in the detrital material to work downward and join the heavier gold which was first deposited.

Concentration of Gold
In a majority of placers the best gold values in the pay streaks will be found immediately above bedrock. In other placers the best values occur on a false bedrock, “hardpan” or conglomerate, which overlies the bedrock. The shape of the channel and the nature of the bedrock are also important factors in the accumulation of the gold. A hard, smooth bedrock does not hold the gold as well as a softer, broken, clayey or decomposed bedrock, schists or conglomerates. Each locality has its own peculiar characteristics, which must be considered in planning the development work. The importance of thorough geological and geophysical studies is not to be minimized in connection with placer mining.
Since the gold is found adjacent the bedrock or false bedrock, it is essential to obtain the depths to the bedrock and the thickness of the fill material. This can be accomplished easily by electrical geophysical methods, due to the difference in electrical conductivity between the bed-rocks and the fill material. In addition, the geophysical work can differentiate the fill material into the lower gravels and the finer clays or soil materials. Where false bedrock is present, the geophysical work can also be depended upon to determine the depth and thickness of this material. Figure 2 shows a typical cross-section from a geophysical survey conducted in central California. The complete outline of the old streambed was obtained, together with the thickness of the lower gravels and the overlying clay and sand fill. With this information the depth of test pits and drill holes were easily determined.

Pay Streaks and Bedrock Contours
Since the valuable placer materials are deposited by the decrease in velocity and change in direction of the flowing water, all portions of the channel will not contain the same values of gold, but the distribution will be very irregular. The pay values are not always at the deepest portions of the old channel, and this, of course, has no relationship to the present stream. After the depth to bedrock has been obtained over the old channel, and the geophysical sub-surface contour maps prepared, a study of the hydraulic conditions of the old channel will give considerable insight to the points where gravel accumulation was favorable.

Determining Depth to Bedrock
The usual procedure in placer work is to take measurements at stations on various traverses across the area being studied, and then plot sub-surface contour maps, showing depth at which bedrock or false bottom are encountered. In addition to obtaining depth to bedrock, the work is conducted to differentiate the lower gravels from the overlying finer materials or clays, depth to water (if below present water course) and structural information having a bearing on the accompanying geological work. This work is conducted quite similar to structural investigations described in previous issues of The Mining Journal (2),

Field Procedure
All electrical methods depend for their operation on two effects: (1) causing an electric current to flow through the materials to be studied, and, (2) detecting, determining the distribution, and the configuration of this electric current. An electric current flowing through the earth will distribute itself in accordance with the relative conductivities of the total material through which the current is flowing. Besides the variations between different rocks, it has been found that fill and detrital areas, mineralized areas, water courses, clay gouges, fault zones, etc.,
have a greater electrical conductivity than the average country rock and therefore will conduct a greater portion of the current. By studying the distribution of current, it is possible to locate such areas of better electrical conductivity. Using a certain configuration of electrodes making contact with the surface of the earth, and a separation between the power electrodes depending upon depth being worked to, it is possible, by passing a current of equivalent value into the ground through the power electrodes, to measure the field or potentials across the area. From the data obtained in such a series of measurements, calculations can be made to give the effective conductivity of the sub-surface material at various depths.

The low-frequency alternating current five-electrode potential and the direct-current apparatus (4), developed by International Geophysics, are employed for all structural investigations of this type. This equipment consists essentially of a set-box and auxiliary power-supply or batteries, and the necessary measuring (5) apparatus, reels and electrodes. The low-frequency instrument set up for operation is shown in figure 1. Since the depth of operation is dependent upon the separation between electrodes, convenient reels arc provided whereby the electrodes may be moved, at increasingly greater distances from the instrument, as the readings arc made. The reels each contain 1,500 feet of special rubber-insulated, flexible wire, and are shown in Figure 8. From four to six reels are employed at each set-up, the number depending upon depth being worked to.

Determining Concentrations of Gold-Bearing Materials

Magnetite and ilmenite (commonly called “black sands”) are both constituents of placer deposits and because of their high specific gravity are dropped or deposited simultaneously with the gold. These materials are highly magnetic and have magnetic permeabilities thousands of times greater than the bedrock. The areas where these materials are concentrated can therefore be detected by magnetic studies made on the surface of the ground (6). In this work readings are taken at regularly located stations in the area and the strength of the earth’s magnetic field measured. The presence of magnetite and ilmenite, because of their high magnetic permeability causes a change in the magnetic field strength as measured at the surface of the ground. By plotting the local anomalies or variations in the earth’s magnetic field, and lines of equal magnetic strength, called iso-dynamic lines it is possible to locate and outline these materials, with their associated gold. This method, therefore, serves as an indirect and reliable means of locating the areas of higher gold concentration.
Interpretation of the magnetic work is oftentimes difficult in regions where complicated geological conditions exist, such as intrusions, faults, metamorphism, etc. Quite often the anomalies caused by such effects masks the anomaly caused by the placer deposit. Proper interpretation of the magnetic data, therefore, requires a knowledge of the geology of the district. In some areas where flows have occurred after the formation of the placer, the magnetic effects of the flow and variations due to its [quirks], mask the effects of the placer deposit. From this, it can be seen that the magnetometer in itself is most effective in locating placers in sedimentary areas.

Concentrations of the “black sands” and other magnetic effects are determined by means of the instruments illustrated in Figure 4. On the left of that figure is the conventional Schmidt-type, vertical component field balance for preliminary work. Final detail work for checking depth and outline is carried out with the International Geophysics horizontal-component electric magnetometer, shown in the right of the figure.

Location of Placers Buried Beneath Flow
As previously mentioned, the magnetic methods are of limited use in locating concentrations of the valuable placer deposits, which have been covered with a flow material. Where such conditions exist, the electrical methods are most advantageously employed for determining the outline of the buried channel. The theoretical aspects of this type of problem are: (1) A simple two-layer problem (flow material overlying the original material) where no old channel exists; and (2) a more complicated three-layer problem (flow material overlying gravel beds and the original material or bedrock), where the channel exists. No difficulty is had in distinguishing between these two cases, and the old channel may therefore be readily located by proper geo-electrical work. Where flows cover an area the geophysical work therefore should only be depended upon to locate the old stream bed. Once the location is obtained, drilling will have to be employed for determining the distribution of gold in the channel. Needless to point out to the reader familiar with placer mining under such conditions, the geophysical work more than pays for itself in saving the promiscuous drilling usually necessary to locate the old channel.

Summary

Important applications of geophysics to gold mining are constantly being made, and definite results obtained. In a great majority of eases, the geophysical work is conducted at only a fraction of the cost of other methods of development. An increasing number of mining companies are employing the geophysical work as a definite step in the development program. The chief role of the geophysical work in placer mining may be summarized as follows: (1) Location of the bedrock and sub-surface stream outline, and (2) concentrations of “black sands” carrying the better gold values. A few drill-holes or shafts, placed in due regard for the geophysical-geological findings, allow the property to be proved up with a minimum expenditure of time and money. It has been repeatedly shown that the geophysical work effects a vital saving of money by minimizing useless drilling or other development work.

Acknowledgments
The writer desires to acknowledge the assistance of Clyde H. Wilson, mining engineer, and John W. Daly, geologist, both of the International Geophysics staff, for their field work and suggestions in preparation of this paper.

Thomas F. Greenfield of Butte, Montana, recently completed a booklet entitled “Montana in Rotogravure.” It contains many pictures of the mining districts in the state.

1. W. Lindgren. “Mineral Deposits” McGraw-Hill Book Co.. 1928. Pages 246-280; M. von Bernewltz “The Prospectors’ Handbook,’ McGraw-Hill Book Co.; C.A. Heiland and W. H. Courtier. “Magnetometer Investigation of Gold Placer Deposit, Near Golden. Colorado.” Technical Pubiication, A. I. M. H.; H. Spurr, “Geology Applied to Mining,’ McGraw-Hill Book Co.. 1926, Pages 243 to 275.
2. Rickard, T. A., Mining and Scientific Press, Aug. 15, 1908.
3. J. J. Jakosky, “Practical Aspects of Geophysical Surveys,” The Mining Journal, Jan. 15, 1931; J. J. Jakosky. C. H. Wilson, S. W. Daly. ‘Geophysical Examination of Meteor Crater, The Mining Journal, April 15. 1981.
4. Detailed process and apparatus patents pending.
5. Detailed process and apparatus patents pending.
6. C. A. Heiland and W. H. Courtier. op. cit. Noel H. Stearn~ ‘A Background for the Application of Geomagneties to Exploration.” A. I. M. E. Technical Paper.

rehab

MINERAL AND LAPIDARY LINKS:

http://www.mindat.org/directory.php

rehab · SOME NEVADA GOLD MINES- LINKS

Location Variety
Keystone Mine, Goodsprings District, Clark Co., Nevada, USA Gold
813 Pit, Olinghouse District, Washoe Co., Nevada, USA Gold
Adamson mine (A. & T. mine; Golden West group; Wannamuck mine), Winnemucca District, Humboldt Co., Nevada, USA Gold
Alabama mine, Awakening District, Humboldt Co., Nevada, USA Gold
Alcalde Mine, Nevada Co., California, USA Gold
Alexander group placer, Battle Mountain District, Lander Co., Nevada, USA Gold
Allison Ranch Quartz Mine (Crossus Consolidated; Stanton), Deadmans Flat, Nevada Co., California, USA Gold
Alpha Mine, Jarbidge District, Elko Co., Nevada, USA Gold (var: Electrum)
Gold
Alpine Quartz Mine, Nevada City - Banner, Nevada Co., California, USA Gold
Alps mine, Treasure Hill, Pioche District, Lincoln Co., Nevada, USA Gold
Altenburg placer, Bullion District, Lander Co., Nevada, USA Gold
Altitude Mine (Windy Mine; Howard McCoy Mine; Van Alder Mine), Jarbidge District, Elko Co., Nevada, USA Gold
Alto Divide mine, Gilbert District, Esmeralda Co., Nevada, USA Gold
Amador Mine (Amador Lode; Amanda), Nevada Co., California, USA Gold
American Canyon placers, Spring Valley District, Pershing Co., Nevada, USA Gold
Ancho Quartz Mine (Consolidaton of Ancho and Erie Groups; Oliver and Holland; Dublin Bay Consolidated; Neuralgaline and Lane/Holland; Nevada ), Graniteville, Nevada Co., California, USA Gold
Annex placer, Battle Mountain District, Lander Co., Nevada, USA Gold
Antelope Canyon placers, Imlay District, Pershing Co., Nevada, USA Gold
Antelope no. 10 claim, Lone Pine District, Washoe Co., Nevada, USA Gold
Antelope Springs District, Nye Co., Nevada, USA Gold
Antelope View mine, Antelope Springs District, Nye Co., Nevada, USA Gold (var: Electrum)
Arctic Group, Washington District, Nevada Co., California, USA Gold
Argus group, Taylor District, White Pine Co., Nevada, USA Gold
Arista Mine, Bare Mountain District, Nye Co., Nevada, USA Gold
Arizona Mine (Turo-Schekles Mine; Turo Mine), Contact District, Elko Co., Nevada, USA Gold
Arkasas Traveler Mine (Mineral Hill Group), Spenceville, Nevada Co., California, USA Gold
Arkell shaft, Wedekind District, Washoe Co., Nevada, USA Gold
Arrowhead Mine, Arrowhead District, Nye Co., Nevada, USA Gold
Artic mine, Jackson District, Lander Co., Nevada, USA
Location Variety
Ashby Gold Mines Inc. Mine, Ashby District, Mineral Co., Nevada, USA Gold
Ashdown mine, Vicksburg District, Humboldt Co., Nevada, USA Gold
Aspen District, Churchill Co., Nevada, USA Gold
Auburn Canyon placers, Sierra District, Pershing Co., Nevada, USA Gold
Auburn mine, Sierra District, Pershing Co., Nevada, USA Gold
Auld Lang Syne mine (Lang Syne mine), Sierra District, Pershing Co., Nevada, USA Gold
Aultman mine, Robinson District, White Pine Co., Nevada, USA Gold
Aurora District, Mineral Co., Nevada, USA Gold
B & M placer, Battle Mountain District, Humboldt Co., Nevada, USA Gold
Babe mine, Olinghouse District, Washoe Co., Nevada, USA Gold
Baby Consolidated Mine, Nevada Co., California, USA Gold
Bald Mountain Bill claim, Union District, Nye Co., Nevada, USA Gold
Bald Mountain District, White Pine Co., Nevada, USA Gold
Bald Mountain mine (Top pit), Bald Mountain District, White Pine Co., Nevada, USA Gold
Baltic Consolidated Quartz Mine (Shirley; Crown Point), Washington District, Nevada Co., California, USA Gold
Banner and Central Mine (Lava Cap; Assissi Quartz Mine), Nevada Co., California, USA Gold
Banner Mine, Gold Circle District (Midas District), Elko Co., Nevada, USA Gold
Bannock placer, Battle Mountain District, Lander Co., Nevada, USA Gold
Barber Canyon placers, Sierra District, Pershing Co., Nevada, USA Gold
Basque mine, Sherman District, Humboldt Co., Nevada, USA Gold
Bell vein, Buckskin Mountain, National District, Humboldt Co., Nevada, USA Gold
Belle of France Mine, Nevada Co., California, USA Gold
Belle Union Mine (North Extension Norambagua Mine), Grass Valley, Nevada Co., California, USA Gold
Belleville Mine, Pilot Mountains District, Mineral Co., Nevada, USA Gold
Ben Franklin Mine, Grass Valley, Nevada Co., California, USA Gold
Beowawe District, Eureka Co., Nevada, USA Gold
Berkeley Prospect, Rough & Ready, Nevada Co., California, USA Gold
Berlin mine (includes Barker Mine), Union District, Nye Co., Nevada, USA Gold
Bethania Mine, Rawhide District, Mineral Co., Nevada, USA Gold
Betty La Verne mine, Imlay District, Pershing Co., Nevada, USA Gold

AFTER OPENING LINK BELOW, DOUBLE CLIK ON LOCALE FOR MORE INFO WHILE ONLINE:

Click to download file

rehab · MINES GETTING DEEPER AS GOLD GOES UP IN VALUE

LA RIMES 11-5-07

Mines deepen as gold climbs

Workers are going to dangerous depths in South Africa as prices top $800 an ounce.

By Michelle Faul, The Associated Press
November 5, 2007

JOHANNESBURG, SOUTH AFRICA -- South Africa's gold companies, already mining at the world's deepest depths, are looking to plumb even deeper veins in a new gold rush spurred by record prices.

The deeper miners go, the richer the ore being uncovered. The price in dangers, though, includes rockfalls, poisonous gas explosions, flooding and earthquakes.

That has stirred up concerns about the safety of miners, who experts say have the worst lot among South Africa's industrial workers.

Some foreign companies have been deterred by the risks here. But Gold Fields Ltd., the country's second-biggest producer after AngloGold Ashanti Ltd., is ready to set a record, digging deeper than 2.5 miles at its Driefontein mine.

A worker was killed there in September by a tremor at just below two miles. By comparison, the deepest mine elsewhere in the world is in Ontario, Canada, at 1.5 miles.

Harmony Gold Mining Co., the world's fifth-largest producer, wants to develop a mine below an existing one at Elandsrand, at a depth of about two miles, which it says would extend the life of the mine by 18 years.

Some 3,200 miners working to deepen the mine shaft there in September were trapped more than a mile underground. They were rescued after some spent nearly three days underground.

At a neighboring mine, two people were killed in an accident a week earlier. And 25 workers mining illegally died in a fire at an unused part of a Harmony mine in early October.

Gold prices topping $800 an ounce on a weak dollar and concerns on inflation have spurred miners to work ever deeper in marginal mines. In 2005, nine mines employing 69,000 workers were considered marginal or loss-making. Today, mining deeper, they're profitable.

Although many miners say it's possible to go deeper and to do so safely, the country's Chamber of Mines has set up a committee to consider the dangers.

Despite the bonanza, South Africa's gold production continues to fall as resources have been depleted. The United States is threatening to win its top position in the world, with Australia and China lagging far behind.

According to the Chamber of Mines, South Africa's production has fallen from a high of 1,000 tons in 1970 to 275 tons last year. Exports fell from 50% of the country's total in the 1980s to 8.2% of exports in 2006.

Last year, South Africa exported 36 billion rand ($5.17 billion) of gold and sold 720 million rand ($103.5 billion) locally, said Alex Conradie, an economist at the Department of Minerals and Energy.

Gold mining remains a vital part of the South African economy. It's a major source of tax revenue and one of the biggest private-sector employers in a country with 25% unemployment. But the number of miners has dropped drastically from 342,439 in 1996 -- when 100,000 miners were laid off as gold prices slumped -- to 137,611 in 2005, even as earnings have increased.

Of 119 people reported killed in South African mines last year, 113 died in gold mines. By comparison, the United States suffered five fatalities in all its metal mines in 2004, according to the U.S. National Institute for Occupational Safety and Health.

The poorly paid miners are the worst off in the industrial sector, said May Hermanus, director of the Center for Sustainability in Mining at the University of the Witwatersrand and a former government chief inspector of mines.

In August, a mine workers' strike won wage increases of 7.5% to 10%. The average miner makes $365 to $511 a month.

rehab · SCROUNGERS WITH NUTHIN, TAKING RISKS TO GET SOMETHING

LA RIMES 11-5-07

Illegal underground hunt takes toll

'Gold pirates' descend into abandoned sections of mines in a dangerous and illegal quest for the precious metal.

By Celean Jacobson, The Associated Press
November 5, 2007

WELKOM, SOUTH AFRICA -- Thobela Booi arrived in this mining town with hopes of landing a job that would enable him to support his wife and child. He ended up 5,000 feet underground, killed by the fumes of a raging fire.

Booi, 30, had been one of hundreds of desperate laborers who risk their lives working in the shadows of legal mining operations, sneaking in through abandoned or poorly secured shafts and making their way through a warren of interconnecting tunnels to the ore.

South Africa is the world's largest producer of gold, and as the bullion price has risen -- and legal mines dig ever deeper to meet the world's voracious demand -- so have the risks these "gold pirates" are prepared to incur in pursuit of the precious metal.

The gold poaching endangers not only the pirates -- known here as "zama-zamas." Haphazard digging -- the miners often lack technical skills -- can destabilize shafts, putting thousands of legal miners' lives at risk.

The pirates can spend weeks, even months underground, with food, drink and even mail ferried to them by runners.

Clandestine mining reportedly produces about $250 million worth of gold a year, but the gold pirates see little of that money. The workers are believed to be recruited by organized crime rackets that ship most of the gold to Switzerland.

The miners, often armed with guns and homemade grenades, have been known to smoke underground and use gas stoves, even in the presence of highly flammable methane gas.

Booi had been missing for six weeks before his body was found. His body was one of 25 brought to the surface at No. 8 Shaft at the St. Helena Gold Mine, outside Welkom, one of the centers of South Africa's gold mining industry.

The bodies were removed by police from one of the mine's underground stations in late September. It is believed the miners died from toxic fumes or got caught in a fire that erupted Sept. 18 and blazed for days at an unused section of the mine, five miles from the bodies.

They had been left by their colleagues, who made an anonymous phone call to mine security telling them where to find the bodies. Some had stickers giving their names and hometowns.

Booi didn't have a sticker. His brother had to identify him among the other bodies.

"I want to know how this happened," said the brother, Siyabulela Tenge, dazed and angry after seeing Booi's corpse at the Welkom state mortuary. "How did he go underground?"

Tenge has worked for the Harmony Gold Mining Co., which runs St. Helena. He has been underground and knows the hot and dangerous conditions. He says his brother was ill-prepared for the work: "My brother wasn't a miner."

There are several police and mine industry initiatives to tighten security and clamp down on illegal mining. In late September, Welkom police arrested 120 illegal gold miners as they surfaced, probably fleeing the underground fire.

The pirates mine the ore and then extract gold using dangerous mercury, often while still underground or in illegal processing plants.

Although the number of illegal miners underground at any one time is hard to verify, anecdotal accounts put it as high as 1,000.

The municipally owned G Hostel, a wasteland of bungalows and sewage on the outskirts of Welkom, is notorious for being a site from where miners are recruited for illegal operations.

A day after police raided the hostel, reporters were shown the remnants of the crude processes taking place there -- blackened zinc sheets and tin containers in which mercury is burned. Large plastic mining pans stood out amid the filth, some with freshly washed silt coating the bottom -- in them a glitter of gold dust.

One miner, who would not give his name, described the hell at the heart of the gold pit: "Sometimes in the mine it is difficult to identify who is working next to you It's so dark."

rehab · KINROSS MINES LINK

KINROSS LINKS:

http://www.kinross.com/news/videos.html

LINK TO KETTLE MINE PROPERTY

the gold hill references in this thread represent the same mine as depicted in the latter part of this link:

http://www.kinross.com/news/index.aspx

The old Round Mountain town was moved, as the pit ate up most of the original townsite. The whole deposit geology has feeds into the Manhattan, Mt Jefferson, and area mining districts.

The company had just started pit development in 1983, after eradicating what was once round mountain. The site where the round mountain was, is now a sizeable hole.

In 1983, small nuggets were occasionally being picked up, and the operation was mostly a hit and miss gig, with several corporate sell offs and turnovers. Gold was there, but it took quite a bit of investment on milling and leaching equipment. and a steady eddie to keep working on the site, testing and exploring. apparently it all paid off.

while it's not too likely that you alls will find something in the wash of this magnitude, the whole area has a lot of gold history, and maybe you'll make out too, while on the off beaten track.

Service wise, Carver's is a decent place to hang out. I'm not sure if Darrough's hotsprings are still up and running (family scores and feuds), but it's great to soak there if it is. I worked up in Kingston Canyon once, and hit down to round mountain to the grocery store, probably twice a week. It snowed a lot while I was working, and you could only tell the highway as it was a wide flat spot in white.

I'd get to the grocery store, and stop to see Mrs. Darrough, sometimes with gifts. not anything like soaking in a hot pond during a blizzard, with only your nose sticking out of the water... the only other place like that is Pagosa Springs, CO

rehab · GOLD IN SCOTLAND EMJ 9 15 1928

E & MJ 9 15 1928

COMMENT AND CRITICISM

Even Scotland Has Had Its Gold Rushes

THE EDITOR:
Sir, In the south as in the north of Scotland, “gold fields” exist; the precious metal is there to be picked up occasionally. In the early twenties, several Lanarkshire miners, then on strike, found “trovering” for gold in Clydesdale, decidedly remunerative. In the north, gold was discovered more than fifty years ago in the Helmsdale Valley, Sutherlandshire, and thousands of adventurers flocked into the district. Hopes ran high with a return of gold to the value of £8,000. In 1911, gold washing was again resumed in the Helmsdale District, but after a short time, the enterprise came to an end.

In the south, however, in the wild tracts where rises the Clyde and the Nith, together with a small part of Peebleshire, there is gold also. The district is bleak and sterile, but its moors and its four streams—Short Cleuch, Mennock, Wanlock, and the first of the Clengoner Water—have been associated for centuries with gold and its seekers. Shepherds still find an occasional grain of the metal in the channels of the streams and burns, and at the foot of the glens.

Cornelius de Vois obtained permission in 1567 to “break the ground, mak (sic) sinks, and pots therein, and to put labourers thereto.” He had six score men at work in valleys and dales, together with lads and lasses. Yet neither history nor tradition hints as to the measure of de Vois’ success or failure. The next gold adventurer was distinctly fortunate if the “Archaeolokgia Scotica” is to be trusted for veracity. Sir Bevis Bulmer, a master of the Mint to Queen Elizabeth, obtained the right to work the Glengoner Water and environs for gold, and apparently he did wondrous well.

Upon Glengoner Water he built a fair country house; he furnished it fittingly; he kept therein great hospitality; he purchased lands and grounds; he kept much stock; and he brought home a water course, for the washing of gold. By help thereof, he got much straggling gold on the skirts of the hills and in the valleys, but none in solid places; which maintained himself then in great pomp, and thereby he kept open house for all comers and goers, as is reported. He feasted all sorts of people that came thither. Thus wrote the historian. Tradition corroborates the record as to Bulmer’s opulence from Glengoner gold.

Wanlock Head, however, had, before that decade, contributed to the riches of the kingdom. Stephen Atkinson, writing in 1619 on “The Discoveries and Historie of the Gold Mines in Scotland,” tells of one Abraham Grey who wrought out of gold, found on the Lanarkshire waste, “a verie fair deep bason” that held “within the brims thereof an English gallon of liquor.” This basin was filled with coined pieces of Lanarkshire gold called unicorns, and both were presented to the King of France, by the Regent Morton.
James I is said to have authorized the expenditure of about £3,000 sterling
—a big sum in those days—in working Carnwath Moor for gold. And the return was about three ounces! One or two miners did better in 1923. As also did a holidaying prospector in 1925; who picked up his income for two years.

But even the Helmsdale Rush cannot be compared for excitement with the rush that accompanied the finding of the precious metal in the east of Scotland, some three generations ago. A young man at the Australian gold diggings happened to mention in a letter home that the gold quartz there had a close likeness to rocks on Lomond Hill. This statement, his father accepted as fact. The gold fever took the old shoemaker, and, having paid a stealthy visit to the place, he satisfied himself that Davie was right. Evening after evening, the old man furtively made his way to the spot, filled his sack with the rock, and betook himself home by different and roundabout paths to evade
prying eyes.

His behavior, his ill-suppressed excitement, and his nightly jaunts caused comment, and then observation on the part of neighbors; and one evening a party of them challenged him as he was filling his sack. By the next forenoon, Kinness-wood and the countryside were gone gold-mad, and the folk flocked in hundreds to Lomond Hill. Some took horse and cart, and returned with sackfuls of the ore piled high, and they that had no wheelbarrow, staggered homeward with heavily burdened shoulders. Many slept alongside their “claims” and the scene next day defies description. What also defies description was the reaction that same afternoon after it was announced that the sparkling yellow particles were merely pyrites, and that the rock was not worth a shilling a ton for road metal. And for that generation, at any rate, the mere mention of
“DAVIE’S DIGGINGS” brought the glint of fury to many decent folks’ eyes.

N TOURNEUR
THUNDERSLY, ESSEX, ENGLAND
September 15,1928.—Engineering and Mining Journal

rehab · BROMOCYANIDE TO GET GOLD FROM ORE EMJ 9 15 1928

Bromocyanide Treatment for Gold Ore

WESTERN AUSTRALIA is turning attention to refinements in the application
of the Sulman-Teed bromocyanide invention, whereby the roasting of a sulpho-telluride gold ore is unnecessary. Mr. C. B. Blackett, well known for his work when metallurgist of Golden Horseshoe Estates, has been conducting a research, according to an account in our London contemporary, The Mining Magazine.

The need for precise chemical control has been demonstrated, and experiments have shown that a high extraction of the gold is obtainable by a treatment comprising separate agitation with cyanide, and then bromocyanide solutions, in the order stated. A two-hour agitation with cyanide and a one-hour agitation with bromocyanide has been found to give maximum results on one ore, three hours with cyanide and two hours with bromocyanide being the best combination on another.

This change in the character of the solvent, incidentally, is in line with the conclusion that residue gold may be, in some instances at least, adsorbed gold, especially if excessively fine grinding has been practiced. A change in the physical character of the solution may alter surface-tension influences to an extent permitting the release of gold held thus. Picric acid adsorbed on platinum black, from an aqueous solution, is insoluble in water, but is immediately released if alcohol be added to the water. Similarly, it is not always effective to continue the treatment of an ore with the same solution, or the same wash, even in intermittent steps if the ore has been ground so finely that adsorption effects have played an important part in the retention of the gold on the surfaces of the gangue particles.

This is straying from the subject, however. The essential value in Mr. Blackett’s work lies in the conclusion that ample opportunity exists for further research, even in connection with an invention that may have been developed a great many years ago, and forgotten by most metallurgists. The field for extended use of a halogen as an activator in a solvent for gold has not been adequately explored.

With the significant changes made in recent years in the more efficient and more economical production of bromine—particularly in regard to its extraction from the salt-plant bitterns in the San Francisco Bay region—it might be advisable again to study the scope for the use of a double salt such as bromocyanide in the treatment of a moderately as well as a highly refractory gold ore.

403
September 15, 1928— Engineering and Mining Journal

rehab · WORLD'S GOLD RESOURCES TMJ 3-15-1931

for MARCH 15, 1931

The World’s Gold Resources

An analysis of the gold situation.
By ROBERT N. BELL, EconomIc Geologist, Boise, Idaho.

The first of a series of articles on the money metals and their relation to world prosperity.

In the present distressed condition of American and foreign affairs, the principal medium of business activity, money metals, is being discussed with increasing interest.

In the creation of wealth and property from raw materials by human labor, mental and physical, money in acceptable form is the primal, motivating force, and the restriction of the world’s money medium to gold or its printed paper equivalent, which is now being so voluminously used, with the narrowness and shrinking volume of this single basis of paper credits, together with its knotted and coagulated segregations in the world’s industrial activities, is apparently among the fundamental causes of the present distressing business situation.

The single gold standard of value established by the leading financial minds of the Western world, with the view to better controlling the world credits and price levels, is now on trial and the chief evidence against its sufficiency is two major world wide industrial panics within an eight year period, the second now in full force and effect, with the end not yet in sight.

The single gold standard advocates have arrogated to themselves the exclusive privilege of defining the science of money. But they have little to be proud of in the demonstrations they are now making as to the soundness of their deductions in a matter of such vital importance.

The permanency of any structure is governed by the soundness and breadth of its foundations, and it appears that the superstructure of the world’s credits, built, upon gold alone, is getting so top heavy as to threaten collapse unless more firmly supported by the natural twin money metal of gold, which is silver, whose close affiliation in nature is acknowledged by all competent students of the subject, and whose twin use as money basis with gold has been recognized throughout the ages by students, laymen, and the vast proportion of the less educated peoples of the human race.

The recent report of the Gold Committee of the League of Nations, which seems to be a compilation of the opinions of the ablest authorities of each important gold producing country of the world, and some able fiscal analysts, shows quite conclusively that the peak of the world’s gold production has been reached, and that the output of the metal is due for a rapid decline within the next ten years. This opinion is apparently shared by the single gold standard authorities themselves who handle the world’s monetary supply of the metal, as they have practically taken it out of circulation as money, exhibiting in effect the hoarding instinct of the Hindu in the maintenance of the present limited supply of the metal. The further use of the word “gold” in voluminous bond issues, with the implication of redeemability in that metal, is an offense to common-sense, and unworthy of the public confidence usually placed in responsible financial institutions.

I am fully in accord with the findings of the experts in the matter of the present and future gold production of the world. The annual production of new gold in the world totals approximately $400,000,000 in value, but it must be appreciated that fully half of this output is absorbed in the arts and industries for use in personal adornment and hoarding purposes, and does not function as money. The desire for gold for personal adornment is not confined to the pagan instinct, but is a weakness conspicuously exhibited by civilized people, who need look no further than their own waistlines for a proof of this statement.

In computing the present and future supply of gold, a fact must be taken into account which has not been overemphasized by the authorities, i. e., that a very large proportion of the total gold now in human hands, represents the mining activities of the erosive forces of nature over millions of years of time in the deposition of the metal, as shallow placer deposits conveniently laid out on the surface of the earth, and readily available with the crudest of tools, after its position was discovered; that the surface of the earth has been very thoroughly combed for the discovery of additional sources of gold supply of this kind, with no very important results during the past 30 years; that future discoveries of this class of gold deposit of major importance have practically passed out of the picture, and that the present production of gold is predominantly from hard rock vein sources whose recovery often involves excessive capital risks and narrow profit margins.

It would be hazardous of course for any student of geology, technical or otherwise, to express the opinion that virgin gold fields of major importance do not remain to be discovered in the remotest sections of the earth’s surface. And in fact, in the better known sections of gold occurrence, as nature has a way of obscuring her primary metallic treasures in their surface expressions, that sometimes puzzles the specialist. However, such progress has been made along this line of endeavor in recent years as to cause a doubt at least as to the discovery of important new fields, with the possible exception of by-product supplies of the metal, of which there still remains some promising areas for investigation.

The Witwatersrand gold field of South Africa is the outstanding example of vein gold concentration in the history of the industry. The matrix of these remarkable ore deposits, whatever the ultimate source of the metal they contain may be, has some analogy and probable relation to the mining activities of natural erosion, in the fact that it is largely composed of water-worn pebbles, and is in effect a petrified placer deposit of ancient pre-existing earth surface conditions.

These African blanket deposits now providing fully 50 percent of the total annual production of gold in the world, are of such a distinctive type that their duplication in any material degree would probably have been recognized in the quite thoroughly explored portions of the earth’s surface accessible to investigation. According to the consensus of opinion of their own able expert authorities, these African deposits seem definitely destined to a 50 percent reduction in output within the next ten years [stated in 1931].

These authorities give the present proven and probable ore tonnages of a value of about $6.70 a ton, at 820,000,000 tons. And the present annual rate of production at 81,000,000 tons, and it is a matter of simple arithmetic to measure the destiny of this present most important source of the world’s supply of gold.

The same authorities, doubtless with justifiable optimism, give an estimate of several hundred million tons of additional possible ore resources, but of a value per ton considerably below the cost of operation, with a remote prospect of its availability as an additional source of gold supply. American technicians, among whose early conspicuous figures were John Hays Hammond and Charles Butters, played a prominent part in the original beneficiation of these remarkable gold deposits along mining and metallurgical lines. Their lead has been ably followed and kept up to the minute of progress by the British owners and operators, so much so that there is little further to be anticipated in the way of metallurgical economics in the treatment of these ore deposits. This is also particularly true in the major item of production costs, which is labor, now as in the past so predominantly supplied from native workers. And it is probable that these operations involve the lowest wage scale known in the gold mining industry.

In the opinion of able American and European engineers familiar with that gold producing region, the Russian gold fields due to their rigorous climatic situation have already reached and passed their peak of production. And it is interesting to note that fully ninety percent of the production of that region has been derived from shallow surface placer deposits, in which nature paid the largest part of the primal mining and milling costs.

The gold fields of India are of minor importance, and apparently also, in a decadent state of development, production and prospect.

The Australian fields have brought forth nothing of major importance since the discovery of the Golden Mile of the Kalgoorlie area of forty years ago. And while the extensive desert areas of that island continent may still carry some undiscovered resources of major importance, the severity of natural conditions under which they would have to be operated would prove a serious bar to their profitable treatment.

The present prolific gold producing area of Canada, especially of the pre-Cambrian shield, is handled with due respect by the experts and the consensus of opinion in regard to that field is for steady maintenance, and probably a slight increase in gold output for an indefinite term of years. The youngness of this field as a major gold producing area, its vast tundra brush and ice-covered surface, and the natural difficulties of exploration, are the superficial factors in the favorable consideration given to this terrain. Its fundamental possibilities as a future source of gold have been justifiably handled with soft gloves and manifest timidity.

It is recognized that some of its recent centers of production have proven both important and profitable during the flush periods of their operation, after mature development and equipment. Their dearth of associate detrital gold indicates that they are practically intact and have lost little of their primal gold deposition in spite of the fact that they are situated in one of the most deeply and recently eroded areas of the earth’s surface. And that, in spite of their apparent deep-seated persistency in some instances, as at Kirkland Lake, they probably fall into the epigenetic class, are of moderate tonnage capacity, and under modern rapid fire methods of mining are of short life duration.

The most promising exceptions to this general condition of Canadian mining progress east of British Columbia, are the ore deposits of the Sudbury Basin whose structural relations and magmatic associations carry the most conspicuous North American resemblance to the remarkable African deposits, in both gold and copper in the matter of linear distribution. The Sudbury Basin area promises to prove a major source of future gold supply, but only as a by-product from the treatment of associated base metal ores. The operation of these deposits aptly illustrates the time factor contingent capital risk, and technical ingenuity involved in the winning and maintenance of the world’s future gold supply from this type of by-product gold deposit, so ably outlined in D. C. Jackling’s contribution to the League of Nations Gold Committee report.

Even after this geologic province was demonstrated by our Lake Superior copper and iron ore fields, to be the favorable environment for rich metallic mineral deposits, it took our Canadian neighbors a full generation of time with a lot of American financial and technical help, to accumulate sufficient courage to follow the complex low grade Sudbury ore deposits down to the crest of the magmatic metal well they seem to be now approaching in the Frood Mine, whose remarkably rich ore body is probably not an isolated occurrence, either in quality or volume, unless the Sudbury norite laccolith was developed from a constricted pipe-like center of emanation, which, due to its enormous volume, is qestionable.

It is more likely to have had a fissure source distributed with some relation to its great linear extent. And its higher concentrations of ore values are probably governed by the intersection of such a fissure source with the offset breaks for which that great magma made mass is noted. If this deduction has any value, a lot can be anticipated from the further extensive exploration in depth of the synclinal trench with which the Sudbury ore deposits are associated over such a remarkable linear extent. With the establishment of a normal demand for baser metals that we hope future progress will involve, the Sudbury Basin deposits hold the most promise as a permanent source of gold of any of the Canadian discoveries so far brought to light.

The production of gold in the United States has suffered a decline in output of fully 50 percent during the past fifteen years, and the maintenance of the present output of 2,000,000 ounces annually will depend largely upon the activities of base metal ore deposits, and their contribution of by-product gold. This assumption will not meet with the approval of the local promoters of the different gold winning states and districts of this country. And they have some fragmental justification for their contention in some instances.

My own state of Idaho presents an example of this kind. A local district known as the Boise Basin, with a past production record in gold output of upwards of $100,000,000 in value; probably 90 percent of which was from surface placer deposition, has been considered by technical authorities, as largely exhausted of its primary supply of vein gold, by natural processes of erosion. But intelligent engineering activities of the past few years have demonstrated the fact that the vein sources of this very material contribution to the world’s stock of gold, continued their genetic activities long past the period of inception of the placer deposition.

One of these veins known as the Belshazzar, whose outcrop was originally discovered by placer mining operations, has, after a long idleness, within the past four years been developed to a depth of 400 feet, and at that level, afforded segregations of native gold up to nine pounds in weight, far larger nuggets than disclosed in the annals of the old placer operations.

Another mine in the same belt, at one of the deepest points of erosion in the district, was developed prior to four years ago to a depth of 700 feet, and had a fairly authentic record production of $1,000,000 for each hundred feet of shaft development. This deposit in competent hands, with modern equipment, has recently been carried to a depth of 850 feet, where the ore is of higher grade and the gold more conspicuous as native metal, than at any other point in the former history of the operation. This mine is now treating 80 tons of ore a day, and contributing gold to commerce at the rate of 18,000 ounces a year, with the eminent prospect of doubling this output.

Idaho has several other promising sources of vein gold supply. One of these, the Meadow Creek Mine, in one of the most remote sections of central Idaho, now under extensive development by the Bradley interests of San Francisco, falls into the family class of volume and value with the famous Homestake Mine of South Dakota. And in its present stage of development, already carried to a depth of 1,000 feet, promises the justification for a pilot milling unit of a thousand tons a day capacity at an early date.

In conjunction with Eastern Oregon, along the Snake River Canyon, Idaho has an extensive area of potential by-product gold, in great copper bearing porphyry dikes up to two thousand feet wide and several miles in length, that already exhibit tonnage demonstrations running into several millions of tons of 2 percent copper ore, that carries a fairly uniform association of $1.00 gold to each unit of copper value. And I have no doubt that local authorities of other formerly gold producing centers of the Western states can furnish similar promising areas of future gold supply. But it will take a full realization of all the optimism expressed in regard to such sources of new gold, to support the inevitable early recession in output in the present hard worked principal source of supply on the South African Rand.

California, as in the past, continues to be our leading gold producing state. However, its pre-dominant production has been from placer deposits. And these are now restricted to some very minor remnants of this type of deposit. And the remarkably deep-seated vein gold deposits of this state have recently been so edged about with tax burdens and legislative restrictions, as to discourage enterprise in their further exploitation. In addition to its great contributions to gold supplies, California has given the world one of its most conspicuous and successful figures in non-ferrous ore mining and metallurgical progress, especially as it applies to gold mining, Mr. Fred W. Bradley of San Francisco, for his contribution to progress in this vital line of human endeavor, he is a fitting candidate for consideration of the administrators of the Nobel prize.

This remarkable engineering genius solved the only serious problem that confronted our great low grade porphyry copper industry before its substantial Inauguration about 1910, by the previous underground mining, milling and treatment, of more than 100,000,000 tons of hard ore matrix at Treadwell, on Douglas Island, Alaska. This ore containing only 2 ½ dwts. of gold, was treated at a milling cost as low as 15 cents per ton, a figure rarely if ever reached by any of his colleagues in the industry on any scale, and with a net profit to the operation of fully $22,000,000 in dividends paid.

This demonstration of operating economics, for years, stimulated other gold mining activities over the world at large. These Treadwell Island results have since been discounted by the same able authority at the Alaska Juneau Mine, where for the past ten years, he has been and now is, mining and treating more than 10,000 tons of hard rock a day, and making a recovery of 90 percent of primal unit value of less than $1.00 to the ton of ore, with an annual contribution of $8,000,000 worth of new gold to the world’s stock with a very handsome profit in the operation.

This example of the mining and metallurgical economics of gold production, in the face of recent high costs, is a demonstration of the low limit of possibility in this line of endeavor, and an example of technical ingenuity and capital risk that few gold hungry capitalists are willing to emulate. The fixed price of gold, and the recent sharply increased cost of labor, material and supplies necessary in its production, discourages enterprise in this class of investment in available or prospective sources of supply, and while it is possible that few major gold fields in the world still remain to be discovered, from the dead bones of past live production so conspicuously strewn over the gold mining areas of the world, it seems very unlikely that new discoveries, will more than keep pace with the rapidly declining sources of supply still active. And that, as a justifiable basis for the further expansion of paper credits so essential to the industrial progress of the world, gold will have to be supplemented with silver on some fixed ratio agreeable to all the leading nations.

rehab · ORIGIN OF FLOUR GOLD (OREGON) TMJ 3 15 1931

THE MINING JOURNAL

VOL. XIV. No. 20

MARCH 15. 1931

The Origin of Flour Gold in Black Sands

By A. E. KELLOGG, Geologist, Medford, Oregon.

A discussion of the cause of flour gold, or very fine gold, with examples of its attrition in Southwestern Oregon and Northeastern California.

Flour gold, or gold too light, or in too fine particles to save, has long been the "bugbear" of the placer miner and prospector. All sorts of devices have been tried to save it, with usually poor success. It may be so light and fine as to float over riffles, or by adhering to accompanying black sand, or particles of magnetic iron, or, by a certain coating of iron or sulphur, refuse to amalgamate with quicksilver, and be lost.

The origin and cause of this elusive gold may be various. In the first place, it may have been originally minutely disseminated through crystalline, or other rocks, not locally concentrated, or run into solution with quartz, in vein fissures, or wrapped up within, or chemically combined with other so-called gold-bearing ores, but is practically free. Such is probably the origin of much of the tantalizing gold in the gold sands of the Pacific Coast.

Another cause for flour gold is undoubtedly its attrition by waves and other violent waters. As a rule, the further we recede from the crystalline and igneous rocks of the mountains, with their quartz-fissure veins, which are assumed to be the proper habitat of gold in-place, and pass out to the plains, the finer, and more flour, does gold become. This is clearly the effect of the winnowing-grinding action of the streams and other bodies of water, flowing toward the low lands, from the mountains.

A fine example of this grinding and natural milling is to be seen in the very ancient Siskiyou Island, situated in that large area of Southwestern Oregon and Northwestern California, designated as the Klamath Mountains. These lofty mountains were an island in the ocean during Cretaceous times, long before the Cascade Mountains rose above the surface of the water, and by geologists, termed the "Great Siskiyou Batholith." It is, perhaps, one of the oldest pieces of terra firma on the western continent, and compares favorably in age, with the Alps in Europe.

The ancient island is located on the site of the Sierra Nevada, Cascade, and Coast Range, of mountains, a plexus of mountains, including the Klamath Mountain group. The Klamath mountains extend from the fortieth, to near the forty-fourth parallel, and include the Yallo Bally, Bully Choop, South Fork, Trinity, McCloud, Scott, and Salmon Mountains of California, and the Siskiyou, Rogue River, and others, in Oregon. The outline of the 'Island in Cretaceous Sea" and the "Klamath" mountain group is indicated by heavy broken lines on accompanying map.

The major part of the mass of the ancient island is granite, or granitic in character, accompanied with other intrusive igneous rocks, such as diorite, porphyry, and other intrusions of ancient origin, such intrusions having lifted from the depths of the ocean, the sediments that had settled there. These elevations have reached an altitude in some places of 7,000 to 8,000 feet. These sediments thus lifted, were changed from their original horizontal character, to various angles of inclination, and accommodated easy erosion.

Hence we find now only fragments of these early sediments, at the tops of the rather higher elevations, such as limestone, often metamorphosed into marble. These sediments were originally very deep, and erosion carried them away—some back to the ocean, while others were deposited in the valleys as the valleys were formed. These intrusions, and the necessary broken fissured condition in which they, and their beddings have been left facilitated the settling of such minerals as were held in position, or suspended, and all other matter susceptible of being carried downward into seams and fissures as the mass slowly rose. After the whole had arisen above the ocean water, and valleys were formed, or in process of forming, much of the residue resulting from this disintegration was deposited around the shore-lines of the old Siskiyou Island, resulting in the heavy placer deposits, which employed the pioneer placer miners.

Observations will show that all of these deposits were formed along the shoreline of this old island, and that the gold came from it. Thus, into these mountains, as judgment dictates, we must look for the source of the gold. The searches thus prompted have proven correctly that the heavy mineral deposits are found in the seams and fissures of this ancient island.

The Rogue and Klamath rivers drain, by their profound canyons, a vast area in the valley regions of the Klamath group of mountains. These valleys are largely composed of conglomerates of the Siskiyou Batholith. The pebbles, sand, or gravel components of these rocks are derived from many sources, but principally from granite or igneous rocks from the Klamath Mountains. These cementing sands doubtless carried the gold, which, having traveled far from its source, is naturally fine, and must have been reduced still finer by the angry waves and torrents that aided in laying down the Siskiyou batholith. From these cemented rocks, by a stupendous system of erosion and canyon cutting, the gold has, with sand and pebbles, found its way into the bottom of these rivers, and in some cases been deposited in bars and beaches, or along the banks of the streams.

Of the kind of additional milling and comminuting treatment it has received for untold centuries in the depths of the rivers, we may have a vivid object lesson, which will leave no wonder in our minds as to the flour condition of the gold, or as to one of the causes of its particle sizing. The streams, at the time of their annual freshets, are on rampages and impassable. They have narrow passages through solid rock banks, where the boiling waters are forced between narrow walls, as through a pipe. The centers of these narrows become heavily charged with gravel, which piles up a temporary sand and gravel bank, then a sudden and terrific roar, and the roaring is over. In a few minutes, the obstacle is washed away, to re-form again in another point down stream, and the temporarily checked stream rushes on its course. During the floodwater times there are frequent repetitions of the same phenomena in these narrow gorges. Imagine this gravel to carry a percentage of gold and its ultimate grinding by such a terrific milling process is obvious.

The gold found on the beaches of the Pacific Ocean near the deltas of these rivers, has received and is receiving daily, much the same treatment from the waves and tides, let alone what grinding it received in being washed from its source in crystalline rocks, far back in the Klamath Mountains, and on its way toward the sea. There it is deposited and re-deposited in beaches, ultimately consolidated into conglomerates, and gradually raised above the sea, and from these again washed out seaward, and daily milled and turned over, deposited and covered, and re-deposited by the waves of the sea. Is it any wonder that such gold is very floury? What metal could withstand such a process and not become so?

Gold, as it has been said, is one of the widest disseminated minerals in the world, despite its rarity in veins, or in concentrated form. It is safe to say that most of the flour gold found in the various river and sea sands of the world, was never at any time in a concentrated form such as we understand it, in gold-bearing veins and the like, but is derived from gold particles minutely and widely disseminated through the rocks of the world, primarily in the igneous and crystalline series, and secondarily, in the sedimentary rocks derived from these, and lastly in loosely consolidated modern placers, and alluvial deposits.

The analysis of almost every igneous rock bears evidence to this minute gold dissemination. In this respect some igneous rocks are richer in gold than in others: as, for instance, the "pyritiferous porphyry" of Leadville, Colorado, in which the gold may have originally been contained within the pyrites, which are a constituent of that rock, just as mica and hornblende are of many igneous rocks.

In some cases gold has been detected in combination with some common rock forming minerals, and again it appears to occur free, or freed, in certain porphyries, especially in zones of brecciation and decomposition of these. Slates are notorious for carrying gold, sometimes disseminated within their mass, but generally concentrated within minute veinlets, and lenses of quartz, probably segregated from the materials of the slates themselves, or derived from solution from outside, and deeper sources.

Gold disseminated in sandstone, conglomerates, and metamorphic quartzites is not uncommon, sometimes even in commercial quantities. These rocks being consolidated in river or sea beach placers, the presence of gold is naturally to be expected, but commonly in a fine or flour condition. In fact in all cases, either by original deposition, or by combination chemically or mechanically, with other rock-forming minerals, or by long travel or attrition, the gold is in the minute and flour state, and appears so when rocks are broken up, and reduced to sand or gravel by wave or stream, and re-deposited in bars, beaches, placers, and river beds.

In most placers, there is a large proportion of this flour gold, and when coarser gold occurs, even up to small or large nuggets, it is traceable to concentration in veins or veinlets in the vicinity, which may be very small and inconspicuous, such as those traversing the schists of the Nome and Klondike areas, in which there is a notable absence of large workable gold-bearing veins.

Others, as in the Breckenridge region of Colorado, are doubtless derived from concentration in brecciated and decomposed porphyries, or from peculiar veins in place carrying crystallized gold, as in some of our local mines, leaf-gold deposited in shales. With the exception of those derived from these sources of concentrated gold, the gold so universally found and so widely disseminated is in the flour or fine state, and there are many good reasons why it should be so.

An indirect evidence of the wear and tear of the flour gold, experienced in its travel from the parent source, is shown by the character of the minerals associated with it in this region. These are usually the hardest, heaviest and most insoluble known, and in minute state in which they are found, are the relics and sole survivors of the tremendous abrasion by water, which has destroyed all other associated minerals. The common rock minerals associated with placer, beach, or alluvial gold, are quartz sand, the hardest insoluble residium of the disintegration of granite and igneous rocks, and of the sandstones and porphyries formed from these.

Mingled with these are all sorts of heavy and hard silicates and metals, some of them known as gems, such as garnets, rubies, beryls, tourmalines, and even rarer and more valuable stones, from sapphire and topaz, to the diamond. In the metalliferous series, the specimens accompanying placer gold are fragments of the hardest, heaviest, and most insoluble metallic minerals known, such as magnetite, wolframite, etc., and the platinum series, palladium, rhodium, iridium, ruthenium, osmium and iridosmine. Iridium is a hard metal, and 20 percent heavier than gold, while osmium is also a very hard metal, quite infusible and twenty-two and one-half times heavier than water. Iridosmine is of such extreme hardness that it is used for pointing non-wearing pens. In such hard and tough company, it is somewhat remarkable that gold actually exists or remains, considering its comparative softness, and its not absolute insolubility.

Soluble minerals are generally wanting in a placer, although at one time may have been in the placer rocks, the close associates of gold, such as lead, zinc pyrite, and silver-bearing ores. The sorting down and reduction to the heaviest, hardest, and most insoluble class, is somewhat wonderful, and is comparable on a grand scale with the most insignificant processes of artificial jigging and separation in our concentration mills.

Anyone who can invent a reliable means of saving this flour gold will be a benefactor to the mining world, and have a wide area for his operations.

On the coast beaches, the river bars, the irregular values of the deposits, the fineness of the gold, and the difficulty of separating the minute particles of it from magnetic, or black sands, are the main difficulty. The sands are limited as to extent and ephemeral in their nature. In river and dredging placer deposits, the flour gold is apt to be carded over and beyond the plates, by an overwhelming amount of heavy, black sands often accompanying it, or else it is too fine to save and declines to amalgamate. In addition to its fineness, the microscope shows the tiny grains are flat, boat, or cup shaped, causing an air vacuum, permitting them to float and they are consequently lost in the clean-up.

An unusually severe storm raging along this Oregon and California coast lasts for several days. Huge breakers lash the shores, making sweeping changes in the beach modeling, tearing up and tossing about large areas of shingly beach, and piling up the sands in new places and shapes to suit the angry mood of the lashing sea. At last, the angry waves having spent their vengeance, lap peacefully along the shores.

From South Slough, in Coos County, Oregon, to Gold Bluff, Humboldt County, California, the beach miners, following the storm, swarm on the newly made beaches to gather their golden harvest.

The origin and causes of fine or flour gold may be summed up to the original deposition of the metal, in a minute, and disseminated condition and, secondly, travel and attrition.

For more than 70 years the black sands of the Pacific Coast have been delved and tossed about by man as well as nature. At the beginning of beach mining, the reward was aimed at the golden contents of the sands. However, at an early date, platinum, iridium, palladium, and associate metals, were known to exist in these beach placers. In those days platinum was given little attention by miners on account of its then small value in limited market. Many old clean-up dumps have been re-worked for their platinum contents in recent years, with gratifying results.

Government experts, making search for war-metals during the war in this region, said: "There is but little doubt that from the early days of placer mining in Southwestern Oregon, more values in platinum went through the sluice boxes, and was lost, than were ever taken out in gold."

The first record of beach mining was at Gold Bluff, California. The '49ers from middle California were already drifting northward on new quests. Shortly afterward, the northward trek found the Oregon Coast, equally rich. In 1854, an authority, Blake called attention to the occurrence of platinum with the gold at Cape Blanco, Oregon, and stated that platinum was present at a ratio of from 10 to 80 percent of the gold.

In the late 1850's and early 1860's, beach and placer mining was at its height along the Oregon coast, as far north as Coos Bay. The Rogue River Indian war, which was raging made it a very precarious undertaking at the time, however. When easy takings had been cleaned up, the advancing horde of miners moved northward to the Idaho diggings. However, the Old Man of the Sea has since, and still, is generous to the beach miners.

Many ingeniously designed devices for extracting gold, platinum, and associate metals from the black sands on these beaches have been tried with indifferent success. The old-time devices, the sluice box, and the long tom, still remain the tried and trusty method used by successful beach miners.

TIDBITS OF INFO- GOLD RELATED

AMALGAMATION TO RECOVER FINE GOLD EMJ 8 4 1928

ENZLIN-EKLUND PLATINUM & GOLD AMALGAMATION EMJ 10 20 192

GILBERT GOLD CONCENTRATOR DESCRIPTION TMJ 3 30 1929

HOW FIND TO GRIND GOLD ORE THE MINING JOURNAL 6 30 1931

GEOPHYSICS IN GOLD MINING THE MINING JOURNAL 8 15 1931

SOME NEVADA GOLD MINES- LINKS

MINES GETTING DEEPER AS GOLD GOES UP IN VALUE

SCROUNGERS WITH NUTHIN, TAKING RISKS TO GET SOMETHING

KINROSS MINES LINK

GOLD IN SCOTLAND EMJ 9 15 1928

BROMOCYANIDE TO GET GOLD FROM ORE EMJ 9 15 1928

WORLD'S GOLD RESOURCES TMJ 3-15-1931

ORIGIN OF FLOUR GOLD (OREGON) TMJ 3 15 1931