I am revisiting August 20, 1941 from last week to include this story. A little while back we talked about the upswing of interest in mining as war clouds gathered. Some fresh interesting details, San Luis Obispo County is the oldest and one of the richest chrome producing regions in the state.
According to Wikipedia chromium is the 21st most abundant element in the Earth's crust. The deposits can be distributed by volcanic eruptions. Today the largest producers are South Africa, India and Kazakhstan.
I have partially redacted the name of one mine that contained a racial slur. Seventy years ago it was not given a second thought.
Chrome Mining Company May Install Two Mills
By Kenneth Fox
A.H. Wild, of the United States Chrome Mines, inc., lesse of various chrome mines in San Luis Obispo county, announced today that the company is contemplating the installation of two separate ore processing mills in this vicinity.
Wild indicated that one of the plants will probably be erected on the Sweet Water chromium mines, seven miles from Morro Bay on the Atascadero road, and the other at a central point, adjacent to the Castro Extension, London and Pick and Shovel mines, near Camp San Luis Obispo.
Mill flowsheets, plans for processing to be done in the mills have been completed and water permits have been issued according to Wild.
Depends on Survey
Activity in the mines will depend to a certain extent upon the report of United States bureau of mines engineers now doing exploratory work on the Sweet Water and Castro Extension mines, Wild indicated.
M.C. Smith, bureau of mines engineer conducting the local survey, recently sent ore samples from two mines to the Reno Assaying office of the bureau but the report of the ore value has not been returned, he said today.
Size of the mills, Wild said, will be determined by the results of the bureau of mines survey, which, he believes, will justify the installation of two 200-ton concentrating mills with a production capacity of 30,000 tons of high grade chrome concentrates per annum.
Essential to Defense
By concentrates it is assumed that Wild means the commonly milled Cr2O3, chromium oxide, with a percentage of iron and silica. From the mill the concentrates will probably be shipped to ferro-chrome manufacturers in the east for the production of stainless steel, three times the strength of regular steel and essential to national defense.
San Luis Obispo county, as the oldest chromite producing district on the Pacific coast, shares with El Dorado county the distinction of being the largest producing county in the state.
The San Luis Obispo chrome area has not been in heavy production since the last world war, due principally to the severe competition of foreign producers of chromite whose wage earners are paid less than one-fifth of the California miner's wage scale, Wild said. In addition the foreign ore has entered the United States on the eastern coast where the majority of the nation's ferrochrome plants are situated and does not, then, necessitate transcontinental shipping.
Possible development of the Pick and Shovel, Single Jack, Chorro Creek, London, Santa Clara, Mescal, N—–head and Castro Extension mines has been curtailed during the recent months, Wild said, because they are in line with a Camp San Luis Obispo artillery range.
Assessment work on the mines has been possible by the movement of bulldozers and other mining equipment during the night with the permission of army authorities. Wild expressed a hope that longer ranges in areas that do not contain vital minerals will make it possible for work in the area near the camp soon.
High Grade Ore
Grade of San Luis Obispo county ore is indisputably high, according to Wild. Local disseminated ore bodies produce a very pure concentrate containing more than 52 percent chromic oxide with a relatively low iron oxide content of around 16 percent, as compared with the 44 percent chromic oxide and the 24 per cent iron oxide content of Montana ores.