Mendocino County.

Camp Carbon Coal Mine. A description of this property was included in a report on coal in Mendocino County, published in Report XIX of the State Mineralogist, September, 1923. The Carbon Company, owner, was formally incorporated on December 26, 1923, with an authorized capital of $500,000, divided into 10,000 shares at $50 per share. Officers of the company are J. Cal Ewing, president; Max Horwinski, vice president; Frank T. Thompson, secretary; A. L. Fisher, general manager. Offices, 420 Henshaw Building, Oakland, California. Since the last report the company has installed an additional boiler and other equipment, and continued development of their holdings. At a point approximately 525 feet from the main entry a drift was turned south at right angles, which will be extended up the pitch of the bed and connect with a new prospect shaft that will improve the ventilation and give additional access to the coal. The workings as of April 1, 1924, are shown on the accompanying sketch map.

PLATINUM.

The deposit of platinum and gold, located about 2 miles east of Hopland in Secs. 21 and 28, T. 13 N., R. 11 W., has been recently taken over by Lloyd C. Ashley, 1236 St. Charles street, Alameda, and preparations are being made for working it. A report on the property by Logan1 was published in Bulletin No. 85. The property was acquired in 1920 by the Mendocino Mining and Milling Company, Inc., and an elaborate plant, operated by electric power and designed to handle 350 tons per 24 hours, erected. Its operation was not successful, and it was shut down after one or two day's trial, and later dismantled, only the concrete foundations remaining. The present owner will adopt a simple washing system.

Imperial County.

LOS ANGELES FIELD DIVISION.

W. B. TUCKER, Mining Engineer.

SODIUM SULPHATE.

Bertram Sodium Sulphate Deposit is located 2 miles northeast of Bertram Station on the Southern Pacific Railroad, in Sec. 19, T. 9 S., R. 12 E. Elevation 125 feet below sea level. Holdings consist of 320 acres. Owner, E. N. Smith, El Centro, California.

The eastern border of the Salton Sink is made up of Tertiary sandstones and clay beds extensively folded. In the vicinity of Durmid, Bertram and Frink, these beds have been planed off and form a portion of the smooth, sloping desert floor below the old beach line. Generally, however, along this eastern margin of the desert they are deeply eroded and form rough foothills along the base of the higher mountains to the east.

The deposit is mainly thenardite, anhydrous sodium sulphate, which has a crystal form distinct from that of mirabilite, and is not so subject to alteration on exposure to the air. Mirabilite, glauber salt, is here associated with the thenardite, usually occurring on the top of the veins

1C. A. Logan, Platinum and Allied Metals in California, Cal. State Mining Bureau. Bull. 85, 1918.

of thenardite. These parallel veins of sodium sulphate occur in the consolidated clay beds and sandstones which are extensively folded. The general strike of these beds is N. 70° W., dip 30° to 40° N. The

Salt Cake (mainly thenardite, anhydrous sodium sulphate). East open cut, near Bertram Station in the Salton Basin, Imperial County-Photo by E. N. Smith.

above mentioned veins of thenardite have a thickness varying from 8 inches to 3 feet.

The proved area containing sodium sulphate is about one-half mile

wide, and about 3000 feet in length. Samples taken from borings throughout this area are reported to carry 10 per cent to 12 per cent sodium sulphate.

The deposit was originally located by Havens of Imperial Valley, in 1903, as the Glauber Salt Mine, but it was found that the land was owned by the Southern Pacific Railroad. E. N. Smith, of El Centro, purchased the land in 1919. Mr. Smith developed the deposit during the years 1919 to 1921. The property was under lease to E. H. Otto and Company from November 1922, to June 1923, when operations were

Bertram 'Salt Cake' Deposit, in Salton Basin, Imperial
County, showing steam shovel at East open cut.-
Photo by E. N. Smith.

suspended. During this period Otto and Company shipped about 2500 tons of salt cake.

Workings consist of an open cut 600 feet in length and about 14 feet in depth, on the east end of the property. In this open cut, three parallel veins of thenardite interbedded in the clay beds were exposed, being about 4 feet apart, and varied in thickness from 18 inches to 4 feet. In the west end of this open cut, the veins formed a junction and the thickness of the material mined is stated to have been about 6 feet. About 2700 feet west of this open cut is another open cut about 200

feet in length and 14 feet deep. Here two veins of thenardite were worked, which had an average thickness of 2 feet, being separated by beds of clay about 4 feet thick. The dumps from these open cuts are stated to carry 12 per cent sodium sulphate.

Samples of sodium sulphate crystals collected by E. N. Smith were analyzed by Smith, Emery and Company, of Los Angeles, as follows:

Analysis of sodium sulphate from Bertram, California-Sample No. 1:

There is an increased demand for sodium sulphate which is used in the making of wood pulp in the United States by the so-called sulphate process. This process uses sodium sulphate in making sodium sulphide, which is one of the active chemicals in the process, the other being sodium hydroxide. Salt cake for this process should be ground, and should contain at least 95 per cent of anhydrous sodium sulphate. The sodium chloride should not exceed 2 per cent. Sodium sulphate is also used in the manufacture of glass.

Los Angeles County.

California Clay Products Company, offices 315 Western Mutual Life Building, Los Angeles, Victor Kremer, president and R. B. Keeler, secretary, has recently increased the capacity of its plant at Southgate. The company controls large deposits of white burning clay in San Diego County. Their principal products are glazed and colored tile.