RECOVERY OF ZINC.

Some work was done on zinc precipitation from hydrometallurgical solutions by means of SO2, with satisfactory results, except for ores containing large excesses of iron and manganese. A simple and cheap means of removing both is being sought.

Cooperative work on zinc residues has begun with a view to obtaining a maximum extraction of zinc from sludge by leaching.

SMOKE INVESTIGATIONS.

The State of Utah and the city of Salt Lake have each appropriated $5,000 to be used in investigating methods of abating smoke in Salt Lake City, in cooperation with the Bureau of Mines. During May, F. K. Ovitz, superintendent of the Seattle station, made a preliminary investigation of conditions at Salt Lake City and submitted his recommendation to D. A. Lyon, the supervisor of stations. The work will be under the direction of the bureau.

SEATTLE STATION.

GENERAL STATEMENT.

During the fiscal year the Seattle mining experiment station cooperated with the University of Washington at Seattle, the University of Idaho at Moscow, and the Oregon Bureau of Mines and Geology at Portland. During the early part of the year the work was mainly war minerals investigations; during the latter part of the year investigations regularly assigned to the station were resumed.

In September the ore-dressing work, with the exception of that on flotation under W. H. Coghill, was transferred to Salt Lake City, and the mining, preparation, and utilization of coal received more attention. During the year the investigation of the ceramic materials of the State of Washington was undertaken.

COOPERATION WITH THE UNIVERSITY OF WASHINGTON.

The State legislature appropriated $20,000 to continue the cooperative work for the biennium ending April 1, 1921, and an additional sum of $25,000 to erect a building for a coal laboratory. This building will contain equipment for experimental coal washing, work on the utilization of coal and on ceramics.

Through the action of the board of regents of the university, a temporary addition to the Mines Building is being erected to provide space for experiments in burning pulverized coal.

In cooperation with the University of Washington, four lines of investigation are in progress, as follows: Coal, electrometallurgy, flotation, and ceramics.

COAL.

The coal investigations outlined include: Mining, with special reference to efficiency and safety; washing; storage of pulverized coal, and utilization of the small sizes. Development problems of the Alaskan coal fields are also a part of the work.

COAL MINING.

The coal-mining investigations were in charge of G. W. Evans, coal-mining engineer. A bulletin on Coal Mining in the State of Washington, which discusses the coals, the mining methods, and the costs, was completed and submitted for publication.

The causes of "bumps," or "bounces," which frequently occur under approximately 2,000 feet of cover in the mines of the Utah Fuel Co. at Sunnyside, Utah, were found to be due to movement along two normal faults because of the heavy stratigraphic pressure. Bumps at the No. 11 mine, Black Diamond, Wash., were found to be due to the heavy cover and the manner of removing pillars.

Mr. Evans was selected by Secretary Lane as a member of a party to report on the coal beds being developed in the Matunuska field, Alaska. The other members of the party were G. C. McFadden, chief engineer, and L. A. O. Gabany, geologist, both of the Peabody Coal Co. In September the party left for Alaska and made a general survey of fuel problems.

During the year numerous conferences were held with holders of coal-land leases in the Bering River field to aid them in developing their properties, and conferences were held with the commission sent to Alaska by the Navy to consider establishing a coal station there.

COAL WASHING.

In January Earl R. McMillan was appointed junior mining engineer to carry on coal-washing investigations with Mr. Evans. As a first step float-and sink tests were standardized and the application of the results to the operation of coal-washing plants was investigated.

The work done has revealed a lack of careful washing. At one plant recently sampled, the ash, 19 per cent, was reduced approximately 2 per cent in the sizes over one-half inch and was increased correspondingly in the sizes under one-half inch, the washery loss being 5 per cent. Float-and-sink tests showed a possible theoretical reduction of ash to 12 per cent for all sizes by washing with a recovery of 87 per cent. If this instance is typical of other washing plants in the State, it means that with a coal production of 4,000,000 tons annually, 7,000 freight cars are required to haul useless freight that could be eliminated at the mine.

COAL STORAGE.

Replies to a questionnaire sent to coal operators, large consumers, and dealers indicate that only a small amount of coal is stored in Washington because of the nearness of the mines to the markets and the ability of the consumers to obtain coal at all times of the year. The increasing use of pulverized coal gives rise to storage problems, such as unexplainable fires in bins. Many engineers believe that moisture is an important factor in causing such fires. Preliminary experiments indicate the need of giving the problem further study.

POWDERED COAL.

Because of the inadequate demand for small sizes of coal in the Northwest large quantities of these are wasted. An increased use of powdered coal for generating steam offers a possible means of utilizing much of this material. Under the encouragement of the Pacific Coast Coal Co., the use of powdered coal has progressed and already several plants in Seattle are burning it.

Arrangements were made with the University of Washington to build a small experimental combustion chamber for burning powdered coal. Some of the subjects to be studied are: Sizes of coal, air pressure at burner, effect of moisture, air supply, disposal of ash, effect of burning coal on fire brick, and reactions during combustion. Mr. Ovitz made a trip to Dover, Ohio, to attend the second test of the Roberts by-product coke ovens. A paper on "Ammonia in producer gas" was written for publication in technical journals.

ELECTROMETALLURGY.

F. C. Ryan, electrometallurgist, who went to Ithaca, N. Y., to assist Dr. Gillett in electric-furnace work, resigned from the bureau in September. Charles D. Grier was appointed assistant metallurgist in January. His thesis, "Electrometallurgical and electrochemical industries in Washington," was published by the engineering experiment station of the University of Washington, as Bulletin 5. He also prepared a report on the work done the year before in the rccovery of waste tin.

Owing to delays in receiving certain parts and supplies, the electric furnace equipment was not finally installed until near the end of the fiscal year. Outside interests will be permitted to use the equipment under cooperative agreements, so that excellent laboratory facilities will be made available to those without suitable equipment. An experimental electric furnace has been designed for smelting copper fume.

140922°-INT 1919-VOL 1-50

FLOTATION.

Flotation investigations were under the direction of Will H. Coghill, metallurgist, assisted by Carl O. Anderson, junior metallurgist, who entered on duty February 24.

In the theoretical work on the flotation of ores effort has been made to gain a better grasp of physical and chemical principles that have been brought to attention by various writers. This theoretical work is now well advanced and its application to ore treatment is in progress.

Under a cooperative agreement with the Primos Exploration Co., Mr. Coghill, assisted by J. P. Bonardi of the Golden station, made a practical application at a 200-ton flotation plant treating molybdenite ore of some of the results of the laboratory work. The highly satisfactory results are mentioned in the chapter on the work of the Golden station, page 738.

Under a cooperative arrangement with the Forest Products Laboratory of the United States Department of Agriculture, Madison, Wis., the hardwood tar oils are to be fractionated and their physical and chemical properties determined by the Forest Products Laboratory. The suitability of the oils for flotation will be tested by Mr. Coghill.

a

Papers relating to flotation were published during the year, as follows: "Hand device for flotation experiments," by W. H. Coghill; " "Why water overflows a tumbler and floats glass plates and flaky minerals," by W. H. Coghill and C. O. Anderson; “Approximate quantitative microscopy of pulverized ores," by W. H. Coghill and J. P. Bonardi.

Papers on the experimental flotation of Black Butte cinnabar ore, the experimental and commercial flotation of Primos molybdenite ore, the equilibrium of three-phase systems of two liquids and a gas, and the equilibrium of three-phase systems of a solid, a liquid, and a gas are in course of preparation, as is a bulletin on flotation.

CERAMICS.

In December, Ira A. Williams was appointed assistant professor of ceramics in the college of mines, University of Washington and also ceramist of the Bureau of Mines, a department of ceramics being established in the College of Mines which will cooperate with the bureau.

Mr. Williams made a general survey of the ceramic situation, and started to obtain equipment for a ceramic laboratory in the

a Published in Min. and Sci. Press, vol. 118, Apr. 12, 1919, p. 495; Chem, and Met. Eng., vol. 20, May 15, 1919, p. 537; Eng. and Min. Jour., vol. 107, June 21, 1919, p. 1090. Published in Sci. Am. Suppl., July 27, 1918, p. 52.

Technical Paper 211, Bureau of Mines.

College of Mines. He resigned in May to return to the Oregon Bureau of Mines and Geology.

As a result of efforts to have the clay workers of the Northwest consider the manufacturing and technical problems of the industry and the possible investigations to be undertaken, the second annual convention of the Northwestern Clay Products Manufacturers' Association was held in February at the Seattle station.

ORE DRESSING.

During the first part of the year Thomas Varley and A. H. Fischer, in connection with war minerals investigation problems, made concentration tests of 15 lots of chrome ores, including samples from Auburn, Calif., San Louis Obispo, Calif., Golconda, Oreg., and Cypress Island, Wash. These tests showed that high-grade concentrates can be procured from low-grade ores, with recovery of 75 to 85 per cent of the total chromite.

Concentration tests were also made of manganese ore sent from the Berkeley station, and ore from the vicinity of Baker, Oreg.

CHEMICAL LABORATORY.

The work of the chemical laboratory consisted of the analysis of coal, molybdenum ores, gold and silver concentrates, examination of war minerals, etc. In addition, a rapid and accurate method for determining titanium and chromium in beach sand was developed by E. P. Barrett."

In an attempt to solve difficulties in assaying some low-grade molybdenum ores Mr. Barrett, in collaboration with Mr. Bonardi, of the Golden station, worked out details of a gravimetric and of a volumetric method that gave satisfactory results. The two methods are described in a technical paper."

Equipment for making more accurate analyses of coal was added to the chemical laboratory. The chemical work for the station was done by E. P. Barrett until April 1, when he was transferred to Salt Lake City and replaced by J. Irving Prest, from the Pittsburgh laboratory.

PERSONNEL.

The personnel of the station during the year included Thomas Varley, metallurgist and superintendent, transferred to the Salt Lake City station September 16, 1918; Frank K. Ovitz, fuel engineer and

Barrett, E. P., A rapid method for determining titanium and chromium in beach sand. Min. and Sci. Press, vol. 117, Nov. 30, 1918, pp. 729-730.

Bonardi, J. P., and Barrett, E. P., The determination of molybdenum: Tech. Paper 230, Bureau of Mines. 1919. (In press.)