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By Robert C. Weed

Leaching in place at Cananea began in the 1920's on a limited scale. The first plants were small wooden boxes located underground in the Capote and Oversight mines, and output was low. Scrap iron was used as precipitant. Later several other small plants were started up. Leaching was limited entirely to underground areas, and production remained low. The Veta precipitating plant, the first on a larger scale, was put into operation in the late 1920's. After a period of intermittent service it was rebuilt in 1946 and has since been running continuously.

Jul 1, 1956

WITH the present mobilization program in full swing and the enrollment in engineering colleges dropping off, many solutions are offered to relieve the shortage of trained men in the engineering profession. Industry can absorb about 30,000 engineers annually, according to the Engineers Joint Council, and forecasts indicate that the number graduating will have dropped from 38,000 in 1951 to about 12,000 in 1954. If this condition were to continue there would probably not be enough people with technical training to run industry in four or five years.

Jan 12, 1951

By Fernando Concha, Arturo Barrientos, María Cristina Bustos

Manufacturers referred to high capacity thickening as a filtration operation rather than thickening in spite of the fact that it is performed in thickeners and that conventional thickeners can be operated as high capacity thickeners by changing the feeding level and operate it in a different manner. In this work we derive a phenomenological model for high capacity thickening based on mass and momentum balances. The difference with a conventional thickening is the presence of a surface source within the variable domain. The model can be used to design, simulate and to develop control strategies.

Jan 1, 1995

By S. Robinson Brainard

In 1957 the pay of chief executives in the nonferrous metals industry was well above average when compared with other major industries. Furthermore, it continued to rise last year while sales declined 8.2 pct and profits plummeted 32.7 pct on the average. Compensation of Chief Executives: One of the primary objectives of the survey is to measure year-to-year changes in top-management total compensation as it relates to company size and industry characteristics. Total compensation includes salary, bonuses, and the value of deferred contingent compensation awards.

Jan 10, 1958

By Donald J. McKee

The product sizing and tonnage from a grinding circuit are the end result of a series of linked size reduction stages which always involve: fragmentation in mining; degradation in transport of ore; crushing and finally grinding. A case study is presented which illustrates the substantial effect on autogenous mill throughput of different mining practice. It is shown that it is possible to model each of the size reduction steps of fragmentation, degradation, crushing and grinding. The way in which this predictive capability is used is dependent on the operating constraints of each mine-mill combination.

Jan 1, 1998

By F. E. Heuze, R. N. Nilson, R. J. Shaffer, R. P. Swif

As part of the Unconventional Gas Program at the Lawrence Livermore National Laboratory, we are developing a model that allows for time-dependent tracking of the fluid front and flow pressures during the quasi-static or dynamic fracturing of jointed rocks. Application of the model is directed towards both short fast fractures (as in tailored pulse loading) and long hydraulically induced fractures (massive hydraulic fracturing). The thrust of this research is to determine crack extension characteristics due to specific joint systems and fluid properties and to correlate pumping records with crack behavior in jointed systems.

Jan 1, 1986

By Fathi Habashi

Chalcopyrite can be readily leached with HNO3, but the recovery of elemental sulfur does not exceed 50% under the most favorable conditions. Preheating at 500°C in a slightly reducing atmosphere increases the recovery of elemental sulfur to about 65%. Chalcopyrite can also be treated with HNO3 in a pressure reactor at 110°C to solubilize selectively the copper while iron remains in the residue as an oxide. The recovery of elemental sulfur also improved when preheated chalcopyrite is treated in this way. Stainless steel should be an adequate material of construction.

Jan 1, 1974

By Luis Dr. Sobral

In this study, the removal of zinc, cadmium and copper from an aqueous sulphate solution, derived from the biomass desorption process, was examined by using a reaction system with a three-dimensional high surface area electrode (RNiF). This reaction system was found to be extremely effective in reducing metal concentrations to the ppb range. The effect of cathode potential and flow rate were studied for three different nickel foam porosities. In addition, current- potential curves were recorded, at a rotating vitreous carbon electrode, to deter- mine the possibility of depositing the aforementioned metals separately.

Jan 1, 1998

By J. L. Whitlock

An attached growth aerobic biological treatment process has been developed at Homestake Mining Co.'s Lead operation which not only oxidizes free and complexed cyanides, including the stable iron complexed cyanides, but also thiocyanate, and the oxidation byproduct ammonia. Through the employment of a mutant strain of bacteria which has been gradually and specifically acclimated to the waste, these potential pollutants are mineralized to relatively harmless sulfates, carbonates, and nitrates. The resultant effluent, through toxicological testing, has been shown compatible with the receiving stream, which serves as a cold water marginal trout fishery.

Jan 1, 1985

By C. L. Baker

The total production of petroleum in the Gulf Coast in 1927 was 54.541.180 bbl., .5.655.665 bbl. more than in 1926. The Texas total was 49.129.910 bbl. (Table 1) and the Louisiana tota1 5.411.270 bbl. (Table 2). Louisiana production decreased 278.028 bbl., compared with that of 1926. Spindletop produced nearly 44 per cent. of the Texas total. Initial production in Louisiana amounted to 62.865 bbl. and in Texas to 352.955 bbl.' The Oil and Gas Journal gives a total of 1145 wells

Jan 1, 1928

By Charles E. Mauk, H. William Prengle, Robert W. Legan

A process breakthrough was needed for the complete destruction of total cyanide influent as high as 100,000 mg per 1, or below 1 mg per 1, to produce an influent with total cyanide below the limit of detection. The process uses ozone for the total destruction of cyanide and metal cyanide complexes. It was found that while ozone alone reacted with the iron cyanide complexes too slowly for practical application, ozone at slightly elevated temperature became more effective, and ozone with ultraviolet light became effective enough to permit the design of a successful system.

Jan 1, 1977

By W. Barbarowicz, H. E. Uhland

AT the Noralyn mine and mill of International Minerals & Chemical Corp. in Bartow, Fla., process instrumentation has been incorporated in three departments-mining, flotation, and preparation. Use of the dragline is the most difficult aspect of the mining operation to control automatically. At the Noralyn mine there are two draglines, a Bucyrus-Erie 1250-B with 29-yd bucket and 235-ft boom and a Bucyrus-Erie 1150-B with 21-yd bucket and 215-ft boom. These are equipped with a minimum number of instruments, but further instrumentation would increase the operator's efficiency.

Jan 7, 1957

By William E. Horst, John H. Bassarear

A technique is described which simplifies the standard procedure for measuring the Bond work index of a specific ore and illustrates how to overcome the strict requirements regarding feed size distribution normally encountered in operating plants. Actual results obtained from various process streams in a copper concentrator are presented and the grindability data are discussed in relation to the observed plant performance. This type of information can be used to gain a better understanding of plant behavior and to assist in the evaluation of plant modifications and process control studies.

Jan 1, 1977

By G. V. Basham

"Environmental audit" is a phrase that can raise the blood pressure of otherwise cool and calm corporate personnel. There is widespread concern that any organized effort to find environmental problems will do so and may result in the imposition of substantial liability against the business that engages in such activities. However, such audits can reduce rather than enhance possible liability. Relevant issues include: the role of the attorney in the process, liability risks associated with environmental audits, steps to maximize confidentiality of audit results, reporting requirements and use of audit results in a proactive manner.

Jan 1, 1995

By B. M. Davis, J. Wilkins

The method of conditional simulation is easily implemented on the personal computer when the LU decomposition algorithm of Davis (1987) is employed. This algorithm is fairly compact, yet can generate moderate-sized simulations in a few minutes on a 80286 or 80386-based personal computer. The application of conditional simulation presented here is to generate possible ore inventories from a limited amount of exploration sampling. The simulations can then he examined to decide if the potential inventories are sufficiently attractive to proceed with further exploration. An example showing one application of this approach is presented.

Jan 1, 1992

By J. E. Lawver, B. J. Clingan, R. E. Snow

Response surface methodology is a well-known and powerful technique for determining optimum conditions in flotation systems. One disadvantage is the onerous task of the numerical calculations and curve plotting. This paper describes a system in which the investigator simply selects the range of several flotation variables after which the design of the experiment, data analysis, generation of response surface equations, and response surface plots are automatically carried out using a digital computer and a computer-driven curve plotter. Several typical response surfaces of important variables in phosphate flotation are presented as examples.

Jan 8, 1979

By A. A. Shook

The off gas from the #5 converter at BHP Copper's San Manuel smelter was analyzed continuously over a period of several weeks using an online sulfur dioxide analyzer. These data have shown that the oxygen utilization efficiency of this copper converter was somewhat lower than anticipated, and that oxygen efficiency declines significantly during the copper blow. A sharp reduction in sulfur dioxide generation was consistently observed at the end of the copper blow, which could be used by converter operators to prevent over-blowing and minimize rolling out of stack.

Jan 1, 1999

By Paul H. Lu

This paper proposes an unconventional, simple, and practical method of measuring mining-induced ground stresses with hydraulic borehole pressure cells. The method is a direct ground stress measuring technique. It does not require the value of deformation modulus for back-calculation of stresses; instead, it directly measures the ground stress in situ. The applicability and practicality of the technique are shown by two case studies. The technique may be applied to monitoring a stress buildup that may lead to mine roof failure or to rock and coal outbursts.

Jan 1, 1984

By James D. Cribbes

The .paper examines some variables which influence the quality of iron ore pellets, and which may be modified to meet the specific requirements of blast furnaces and direct reduction processes. Quality parameters defining pellet physical strength, size structure and reduction behavior considered important by the operators of blast furnaces and direct reduction processes are listed. Laboratory results are used to illustrate how feed preparation, and pellet chemistry car1 be altered to meet these specific quality criteria and some aspects of the economic impact of quality demands on the pelletizing operation are discussed.

Jan 1, 1977

By Harold B. Foxhall

THIRTY per cent of the mineral wealth of the United States is obtained from seven states: Arkansas, Kansas, Louisiana, Missouri, New Mexico, Oklahoma, and Texas. This area, which produced 84,727,156,000 worth of minerals in 1948, constitutes an almost complete economic unit in relation to mineral resources essential to industry. All of these states are producers of fuels and some of metallics, but in the field of important nonmetallic industrial minerals the picture is near perfection-a mineral any one of the seven states lacks, one of the others has in quantity.

Jan 5, 1951