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MINERAL EXHIBIT AT AMERICAN MINING CONGRESS.

417

MINERAL EXHIBIT AT AMERICAN MINING CONGRESS CONVENTION, AT SACRAMENTO, CALIFORNIA.

WALTER W. BRADLEY, Deputy State Mineralogist.

In connection with the convention of the American Mining Congress at Sacramento, California, September 29-October 4, there was held an exposition of mining equipment and minerals. The main exhibit was held in a large tent (in the absence of a suitable hall of adequate dimensions) in the open space between the two new Capitol extension buildings, at Ninth, Tenth and M streets, across from the State Capitol. This was made possible through the courtesy and cooperation of the state officials, the Sacramento City authorities, and the Sacramento Chamber of Commerce. The convention sessions were held in the Assembly Chamber of the State Capitol.

The mineral specimens were allotted a prominent space in the center of the main tent, and to the California State Mining Bureau was delegated the general supervision of that portion of the display as well as the specific task of making a representative exhibit of California's

resources.

Creditable displays of their economic ores and minerals were made by the states of Nevada and Oregon, and by the Vancouver Chamber of Mines for the province of British Columbia. Worthy of mention, among these, was a diagrammatic and panoramic representation in the Nevada exhibit of a shale oil reduction plant supplemented by samples of the material and products at the various stages. Colorado also had an oil shale exhibit, in charge of the Colorado School of Mines.

In addition to the general state display installed by the California State Mining Bureau, there were separate displays made by a number of the counties, including San Bernardino, Kern, San Diego, Shasta, Calaveras, Placer, Nevada, Amador, Tuolumne, Siskiyou, San Luis Obispo, Contra Costa, Napa, and San Mateo. The San Bernardino and Kern County exhibits, which included a special collection from the famous Rand District, was in charge of Mr. P. J. Osdick. The San Diego County exhibit, devoted largely to nonmetallics (for which that county is coming to the fore), including gem stones both in the rough and cut, was in charge of Mr. H. R. Jackson of the San Diego Chamber of Commerce. Calaveras County was in charge of Mr. Jarvis Lloyd; and Shasta and Siskiyou counties, of Mr. Louis Carrigan of the Northern California Counties Association. Materials for the other counties' displays were arranged by the staff of the State Mining Bureau, with assistance from the Sacramento Chamber of Commerce. One of the difficulties encountered in arranging a mineral exhibit of that sort is to obtain suitable display cases. Much credit is due the committee of the Department of Mines and Mining of the Sacramento Chamber of Commerce for their assistance in that regard, and to Mr. Charles Paine of the State Fair for the loan of glass show cases. A number of cases were shipped by the State Mining Bureau from our San Francisco headquarters.

The general arrangement of the State Mining Bureau's exhibit adhered to the economic grouping by ores of the various metals and the nonmetallic commercial minerals utilized for various industrial and structural purposes.

In the rotunda of the State Capitol, the gold display was placed in four electric-lighted safes with plate-glass fronts. These were loaned by courtesy of Mr. Ed Wahl of Sacramento. Gold bullion, sponge, placer nuggets, leaf and crystallized gold, and high-grade gold-bearing quartz, to a total value in excess of $100,000, were gathered together there and displayed for the edification and education of the members of the congress and visitors. It is doubtful if as extensive and valuable a collection of gold specimens has ever before been attempted or gathered together for such an exhibit, and it attracted much interest and favorable comment. In addition to the Californian material, there were also gold specimens from Oregon and Alaska.

Siskiyou County's famous collection that has taken prizes and ribbons at a number of expositions and fairs occupied one entire safe. Notable among others were: Retorted sponge from a recent crushing, and chunks of ore that were more than half gold, from the Independence Mine, Hamburg Bar, Siskiyou County. Crystallized and leaf gold from the Red Ledge Mine, Washington, Nevada County; also from the Shore Mine, near Jamestown, Tuolumne County. A crystallized specimen (see front row, center, top shelf, in photo) from Yankee Jim's, Placer County, resembling a California Bear in outline.

In addition to the gold, a number of cut gem stones were shown, including diamonds from Cherokee Flat, Butte County; also kunzite and tourmalines (red, green, and pink) from Pala, San Diego County. One of the kunzites, known as the 'Pala Chief,' weighs 103 carats, stated to be the largest cut kunzite gem in existence, and is valued at $2,000. There was also a beautiful ruby-red tourmaline of 53 carats weight called the 'Tourmaline Queen' and valued at $1,000. Both of these stones are the property of the Pala Chief Gem Mining Company of San Diego.

We wish to here express the appreciation of the State Mining Bureau and the mining public as a whole to the several operators of properties and the owners of specimens, for their courtesy and interest in lending their valuable material for the purposes of this display which so strikingly illustrated this important resource for which the West, and California in particular, are justly famous.

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COPPER RESOURCES OF SHASTA COUNTY.

By W. B. TUCKER, Mining Engineer.1

DESCRIPTION AND LOCATION OF COPPER DISTRICTS.

The copper region of Shasta County is about 30 miles in length, and about 15 miles in width, extending nearly east and west across the Redding Quadrangle of the U. S. Geological Survey, and embraces three actively producing districts known as Iron Mountain, Bully Hill, and Ingot, which are separated by a dozen miles of country where as yet no large bodies of copper ore have been found.

The Iron Mountain district is the largest and by far the most important region. Iron Mountain lies just outside of the border of the Redding Quadrangle, northwest of the old town of Keswick, and from this locality the district extends nearly northeast for 25 miles to and beyond the Mammoth, and has a width of about two miles. It comprises the holdings of the Mountain Copper Company, Pittsburgh-Mount Shasta Mining Company, Balaklala (under lease to Mammoth Copper Company), Trinity Copper Company, Colma Copper Company, Golinsky Copper, and a number of other smaller mines.

The Bully Hill district comprises an area scarcely three miles north and south by two miles east and west, and includes the Bully Hill, Rising Star, Arps, and Copper City lodes, besides a number of prospected claims on the south and southwest slope of Horse Mountain. (Plate I.)

The Ingot district, which is on the east end of the copper region, has an area of scarcely two miles north and south by three miles east and west, and includes the Afterthought, Donkey and Woodrow Wilson mines.

Geology. (Excerpts taken from Redding Quadrangle on geology of district.)

The country rock of the copper deposits is practically the same throughout the region, but not all the same age. It is chiefly rhyolite and tuff, and here and there a trace of included sediments.

Character of Ore Deposits. The copper ore deposits are lenticular lenses or zones of disturbance in which the country rock is crushed and sheared, thus producing the channels for circulating waters, and greatly enhancing the possibilities of the mineral solution and deposition.

Fissure Systems. The rocks of the copper region have experienced disturbances at many periods extending over a wide range of time. The system of fissures is confined to three groups: (1) The early fissures filled at least in part by igneous rocks of the pre-Cretaceous eruption, (2) the fissures bearing ore deposits, and (3) the fissures of the late Cretaceous or post-Cretaceous age.

Ore-bearing Fissures. The fissures which gave access to mineralbearing solutions and thus permitted the formation of deposits of copper and auriferous quartz, originated chiefly during the epoch of rock crushing and mountain making about the close of the Jurassic. This is indicated by the fact that the fissures bearing ore have been found in the Jurassic rocks, but not in the Cretaceous. The important

1ACKNOWLEDGMENTS. The writer wishes to acknowledge the uniform courtesy extended him by owners and operators of mines throughout the Shasta Copper Belt.

ore-bearing fissures of the copper districts are irregular in trend. The greatest extension of the copper region is in a direction about N. 80° E., while that of the several districts range from N. 50° W. to N. 30° E.

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MAP OF A PORTION OF THE SHASTA COUNTY COPPER BELT EAST OF THE SACRAMENTO RIVER, INCLUDING THE BULLY HILL DISTRICT, SHOWING THE PRINCIPAL MINING PROPERTIES.

The general trend of the Iron Mountain district is N. 30° E., but the strike of its ore-bearing fissures rarely conforms to the general direction. The strike of the ore-bearing fissures about the head of Motion and Spring creeks varies, but the principal mineralized fissures usually have

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