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Jan 1, 1896

By H. H. Reamer, B. H. Sage, J. S. Billheimer

Jan 1, 1949

Jan 1, 1938

Jan 1, 1934

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Jan 1, 1938

By J. W. Pugh

VANADIUM has only recently received consideration with respect to structural applications. It would appear likely to find service where its high electrical resistance and constact temperature

Jan 1, 1958

By D. N. Sutherland

The cassiterite flotation circuit at the Renison concentrator has operated with increasing levels of automatic control since late 1981. The circuit operates at high levels of recycle which make it difficult to control manually so that the initial control strategy was to stabilize the mass flows around the circuit prior to circuit optimization. Control of the air supplies to the flotation banks was introduced to achieve this stabilization and initial results indicated that some success has been achieved, as indicated by improvements in the overall circuit performance and reduction in the stream variabilities. These improvements were gained through control of the major recycle to the roughing stage which dominates the circuit behaviour. Feed-forward control of collector addition has also been introduced successfully, but attempts to control the final concentrate grade have been less satisfactory. This work is continuing and the objective of current activity is to include the three cleaning stages in an overall circuit control scheme as a first phase of metallurgical optimization of the operation.

Jan 1, 1984

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Jan 1, 1938

Jan 1, 1928

Jan 1, 1942

Jan 1, 1929

By Dale C. Matthews, Donald L. Simpson

Hecla Mining Company's Lakeshore Mine and Metallurgical complex near Casa Grande, Arizona, is the first plant in North America to utilize the roast/leach/electrowinning process for production of cathode copper from sulfide concentrates. Oxide copper ores are also mined at Lakeshore. Using sulfuric acid and sponge iron by-products of the roast/leach operation, the oxide ore is leached in vats, the copper is precipitated with iron and recovered as cement copper. This paper will describe the roast/leach facilities and discuss the operating conditions at which more than 95 percent of the copper in concentrate is made soluble in acid solutions while less than 5 percent of the iron is rendered soluble. More than 97 percent of the sulfur contained in concentrate is captured either as strong sulfuric acid or as soluble sulfates in leach liquors. The iron rich residue after leaching is pelletized and reduced to sponge iron in an SLRN reduction kiln.

Jan 1, 1981

Jan 1, 1936

By E. C. Reed

Drilling operations in Nebraska during 1942 were reduced to approximately 50 per cent of the previous year's record. Forty- No new fields were discovered, but the Barada field was extended and developed. Deeper drilling in the Dawson field was disappointing in view of the high expectstions held for the Viola, but some small Viola production did result, the first from

Jan 1, 1943

By J. E. Dorn

A STUDY of the increase in density of copper powder as as a function of the time and temperature of sintering has been previously reported.' The present note will describe the results of a series of experiments under conditions similar in all respects to those of the first series, except that

Jan 1, 1951

Jan 1, 1959

By W. M. McKewan

Jan 1, 1962

By E. C. Reed

Drilling operations in Nebraska during 1942 were reduced to approximately 50 per cent of the previous year's record. Forty- No new fields were discovered, but the Barada field was extended and developed. Deeper drilling in the Dawson field was disappointing in view of the high expectstions held for the Viola, but some small Viola production did result, the first from

Jan 1, 1943

(Under this heading will be published notes sent to the Secretary of the Institute by members or other persons introduced by members.) Member, also Assoc. Mem. Am. Soc. of C. E.; excellent technical education, and best of references covering 12 years in responsible charge of work; experienced in surveys, construction, prospecting, mine

Jan 12, 1917

Jan 1, 1948