northern California and southern Oregon." No chromite deposits have been found within 40 miles of the 

 Atlantic or Gulf coasts and consequently no offshore deposits can be inferred in these regions. 



Inasmuch as the quantitative ratio of segregated chromite to ultramafic rock in the CaUfornia-Oregon 

 area is infinitcsmal and no reliable means has been devised to locate chromite segregations under even a 

 thin cover, it is unlikely that lode or bedrock deposits will be found in the continental shelves. 



Black sands are a possible but not promising source of chromite in offshore deposits because most 

 chromite in black sands is derived not from segregations but from accessory chromite in ultramafic 

 which has a high (undesirable) iron content. 



It has been estimated' that raised and modern beach reserves of chromite in Oregon contain three 

 million long tons of black sand, two thirds of which may exceed 5 per cent of Cr2 O3 and the remaining 

 third 3-5 per cent CtjOs. The black sand beach and terrace deposits range from one to 42 feet thick up 

 to 1 ,000 feet wide, and from several hundred feet to about a mile long. 



In spite of the fairly substantial tonnage indicated in Table 1, the general outlook for offshore 

 chromite production over the remainder of the century is poor in view of the fact that it has not yet 

 been possible to mine similar onshore deposits at a profit. 



Table 1 



Heavy mineral content of black sand deposits on 

 the continental shelf of southern oregon 



Source: Estimates by H. E. Clifton, Geological Survey. 



Recent studies by the Geological Survey and University of Oregon have led to the identification of 

 seven deposits on the shelf off southern Oregon at depths ranging from 60 to 480 feet.* The best 

 deposits are about 8 miles long and 2 miles wide. Their thickness is unknown but assuming it to average 

 15 feet, and assuming a mineral concentration similar to that in the nearest onshore black sand, H.E. 

 Clifton has estimated the tonnage of some of the heavy minerals in these deposits as shown in Table 1 . 



COAL 



Uses. Most bituminous coal is burned for heat and power production, or carbonized to produce 

 metallurgical coke. Anthracite coal use falls into two broad categories: 1) as an energy fuel and 2) as a 

 source of industrial carbon. Lignite is used principally as a fuel for residential and industrial heating and 

 for generating electrical power. 



T. P. Thayer, commodity geologist for chromite. Geological Survey, unpublished report, 1968. 



'a. B. Griggs, "Chromite Bearing Sands of the Southern Part of the Coast of Oregon," Geological Survey Bull. No. 

 945-E, pp.v, 113-150, 1945. 



*V. E. McKelvey et al, "Potential Mineral Resources of the United States Outer Continental Shelves," unpublished 

 report of the Geological Survey to the Public Land Law Review Commission, March 1968. 



VII-131 



