berry, N. C., a pilot mill was installed at the deposit to produce concentrates for the Salisbury sponge iron pilot plant. The highest quality sponge iron ever made in substantial amounts was obtained from these concentrates. At Minneapolis, experiments were completed on the Brassert bubble hearth-type of reduction with hydrogen, and work was continued on shaft-furnace reduction of iron ore glomerules. At Salt Lake City, tests were continued on smelting and leaching methods of extracting iron and titania from the titaniferous magnetites of Iron Mountain, Wyo.

To increase supplies of critically needed acid-grade fluorspar, commercial milling of material stock-piled by the Metals Reserve Company was made possible by Bureau of Mines laboratory and pilot-plant flotation tests at College Park on Spanish fluorspar of high metallurgical grade and at Rolla on similar Mexican and domestic material.

Nonferrous Minerals

In the field of the nonferrous minerals-lead, zinc, copper, tin, and the various pegmatites-the Bureau of Mines simultaneously carried on a far-reaching exploratory program, a broad research and development plan, and a major drainage project.

The exploration of 28 lead and zinc deposits in 12 States disclosed large reserves in Illinois, Idaho, Nevada, Kansas, and Oklahoma. Bureau engineers also examined 130 additional deposits during the fiscal year.

Despite shattered, caving ground and heavy inflows of water which retarded progress, the Leadville tunnel in Lake County, Colo., was advanced 4,800 feet or nearly a mile in the fiscal year 1945, bringing the total advance to 6,600 feet. This tunnel project, undertaken by the direction of the Congress, was designed to provide permanent drainage for 84 mines which have been flooded and idle since 1933. The purpose was to make available, upon its completion, an estimated 4 million tons of zinc, lead, and manganese ores, and revive the formerly productive Leadville district.

A major low-grade copper deposit was confirmed in Pima County, Ariz., and another deposit of considerable promise was delineated in Coconino County, Ariz., as the Bureau of Mines carried out 16 exploratory projects for copper in 9 States. Another 85 deposits were examined by Bureau engineers. Private interests are conducting further exploratory work on the Pima County deposit.

Meanwhile, considerable beneficiation work was done on ores of copper, lead, and zinc at Salt Lake City, Utah; Rolla, Mo.; and College Park, Md. A pilot plant for reduction of zinc with methane gas was completed at Rolla and breaking-in operations were conducted. Cooperative investigations were continued with a commercial firm on improvements in the smelting of lead and zinc.

A lode deposit of tin on the Seward Peninsula of Alaska, which has greater potentialities than any other known domestic source of tin, was tested through diamond drilling by the Bureau of Mines. Another tin deposit was explored in California.

Two mercury deposits, both in California, also were diamond-drilled by the Bureau. One of these, in Napa County, is estimated to contain 10,000 flasks of recoverable mercury sealed in low-grade ore reserves. Six other mercury deposits were examined by Bureau engineers.

Six investigations in as many States were conducted on pegmatites that yield feldspar, mica, beryl, tantalum, and lithium minerals. The principal objective of this work, which included explorations of many separate deposits, was to stimulate production of the strategic mica used in radio sets and aviation spark plugs. Forty-eight additional deposits of mica were examined. A flotation flow sheet developed several years ago in the Bureau's laboratories at College Park, Md., and Tuscaloosa, Ala., made possible the erection and successful operation of a 750-ton-a-day mill at Kona, N. C., to supply feldspar of the grade and in the amount needed.

Nonmetallic Minerals

Anticipating a major postwar demand for the commodities made from nonmetallic minerals-including building materials, insulating products, fertilizers, paints, pigments, and inorganic compounds-the Bureau of Mines explored 12 deposits in 11 widely-scattered States and Alaska. These included sillimanite, potash, optical calcite, and asbestos deposits, together with 2 barite and 6 corundum deposits.

Georgia's and South Carolina's huge deposits of sillimanite, a material used in the manufacture of refractory brick for hightemperature furnaces and spark plugs, hold promise of national self-sufficiency in this commodity, which the United States heretofore has largely imported. Mineral-dressing investigations at College Park and Tuscaloosa developed a procedure for grading sillimanite up from 20 to 98 percent purity with high recovery, and tests at the Electrotechnical Laboratory at Norris, Tenn., indicated that sillimanite concentrate can be substituted for scarce kyanite in refractory brick.

Approximately 50 deposits of nonmetallic minerals were examined by Bureau engineers. Their minerals include silica, oil shale, quartz crystals, kyanite, pearlite, pumice, talc, pyrophyllite, bentonite, and vermiculite.

Light Metals

Fortunately, the supply position of the United States improved during 1945 in the light metals-aluminum, magnesium, and their alloys. Hence, it was necessary to mine and use only a small portion of the reserves of bauxite-estimated to total 90 million tons of all

grades-indicated by large-scale exploration by the Bureau of Mines in Alabama and Arkansas.

Work continued at several laboratories and pilot plants on the extraction of alumina from low-grade bauxites, clays, and alunite, with particular emphasis on assisting in operation problems at Governmentowned, semicommercial alumina plants. At Bauxite, Ark., construction of a pilot bauxite mill was completed, and breaking-in operations were started. At Rolla, Mo., laboratory beneficiation studies were made on bauxites to be treated in the mill. At College Park, Md., progress was made on the recovery of magnesium and aluminum from drosses, powders, and dust. Air tabling of magnesium sawdust recovered magnesium metal of suitable purity and particle size for reduction of titanium.

Significant advancements were made in the development of a new commercial metal, ductile titanium. This project was transferred from Salt Lake City, Utah, to Boulder City, Nev., where a production rate of approximately 100 pounds of metal a week was attained. A project was begun at the Albany, Oreg., Electrodevelopment Laboratory on the reduction of zircon, which is present in Oregon beach sands. As both titanium and zirconium are reduced with magnesium, their production might offer a post-war outlet for magnesium metal. The Albany laboratory will continue development work on the carbothermic magnesium reduction process, which had been studied at Pullman, Wash., and in cooperation with the Ford Motor Co. at Dearborn, Mich.

COAL AND COAL PRODUCTS

To combat the problem of solid fuel shortages which persisted in 1945, the Bureau of Mines promoted methods for more thorough mining of coal, improved preparation and upgrading of coal for specialized uses, and secured better utilization of coal and coal products in industrial establishments and homes.

In conjunction with its well-known fuel services, the Bureau analyzed more than 20,000 samples of various fuels during the year in its laboratories. This work helped maintain fuel efficiency at Army and Navy installations, helped keep war industries operating at full capacity, aided Federal coal-mine inspectors in preventing coal-dust explosions, guided Government fuel-purchasing agents, and assisted the coal exploration and research work of the Bureau. Maintaining its consulting service for Government agencies in the purchase and utilization of fuels and fuel-burning equipment, the Bureau saved thousands of tons of coal by recommending changes in the operation of equipment at many Army camps, eliminated difficulties that prevented continuous boiler operation at two Navy land stations, chose fuels for new Veterans' Administration projects, and

made scores of fuel-efficiency and equipment-acceptance tests. Federal boiler plants, including those at all Army posts, were safeguarded against boiler-scale corrosion and caustic embrittlement by the Bureau's feed-water conditioning service, and studies of corrosion in condensate return lines resulted in better protection for $300,000,000 worth of steel equipment.

Thousands of volunteers were enlisted in a Nation-wide fuel efficiency program aimed at saving 29 million tons of coal a year and proportionate economies in the commercial and industrial use of other types of fuel and energy. More than 13,000 plants and establishments pledged cooperation as a network of some 20,000 engineers and fuel experts-virtually all serving without pay-carried the campaign directly to commercial, industrial, and institutional fuel consumers. Thousands of copies of publications incorporating up-to-date information on such subjects as coal storage and use were made available to industry.

Also directed at fuel-shortage problems, Bureau studies resulted in the establishment at Philadelphia of a packaged-fuel plant for converting 150,000 tons of surplus anthracite fines into a more convenient fuel and in the blending of anthracite fines with bituminous coal for stoker use.

Coal Mining and Exploration

Cooperating with anthracite producers, the Bureau studied problems of mine flood prevention and better methods of mining the thin, steeply pitching beds that constitute a large part of remaining reserves. Determinations were made on the economic limitations of light equipment for stripping coal from outcrops in mountainous areas. Coal fields of the West, South, and East were explored for minable reserves of coking coals, and the Pacific Northwest was scoured for adequate fuel supplies to relieve an acute shortage in that area. Laboratory petrographic examinations and coking tests were made on more than 150 coals of the United States, Chile, and China, and methods of increasing the production of Chilean coals were investigated.

Gas- and Dust-Explosion Research

To reduce explosion hazards in coal mines and many types of plants, tests were made on industrial powders, dust, and vapor-air mixtures. Recommendations and safety codes were formulated for plants producing explosive materials and dust, and specifications for conductive footwear and flooring materials were developed to lessen hazards of explosions from static electricity. Conditions permitting the safe use of larger charges of explosives in coal mines were determined by tests,

Coal Preparation and Storage

To augment diminishing reserves of high-rank coking coals and to up-grade marginal and lower-rank coals, studies were made on preparatory treatments to reduce sulfur and ash in coking coals and on the salvaging of refuse coal at points of origin. The distribution of sulfur in the coking coals of Greene County, Pa., was determined, and concentrating tables were found effective for recovering coke breeze from dumps. Two Alabama companies based designs for coal-preparation plants on washability data provided by the Bureau. Laboratory studies were made on the storage properties of about 35 coals.

Coal Combustion

Keeping pace with new developments in order to improve its service to industry, the Bureau of Mines became the first in the United States to employ the electron microscope for determining the surface area and size distribution of powdered coal. Needed information was provided on the burning characteristics of war-emergency fuels, including some produced by new processes. The Bureau developed apparatus to measure the thermal conductivity of coal-ash slags, permitting the study of slag deposits on boiler tubes from melted coal ash to provide the data required for improving the design and operating efficiency of boiler furnaces. Fundamental data were obtained in a study of more than 200 ash analyses, and studies of slagging and atmospheric conditions around furnace walls demonstrated one cause of tube failure and lessened boiler "outage," or time lost in maintenance and repairs.

Coking and Gasification Studies

Progress was made on two processes which offer promise of a cheap source of materials for a multitude of purposes. In the first, carbon monoxide of relatively high purity was produced by burning pitch coke or petroleum coke with oxygen. In the second, the Nation's immense reserves of lignite were brought closer to industrial use through the successful testing of a large retort for producing carbon monoxide and hydrogen from lignite by gasification. Evaluation of the gas- and coke-making properties of coals from newly developed fields greatly benefitted the coke and gas industries. Greater production and a more uniform grade product were obtained without increased capital or labor costs at several coke plants using the Bureau's data on coal bulk-density control, and others receiving direct technical assistance also reported higher operating efficiencies and increased outputs.

Synthetic Liquid Fuels

Major strides were made in the fiscal year 1945 toward the objectives set forth by the Congress in the Synthetic Liquid Fuels Act