Several research groups have spent considerable time investigating coarse ore leaching. Coarse ore leaching includes both heap and dump leaching. The terra “heap leaching” will be used in this paper to mean any type of coarse ore leaching. The results of their work are generally in agreement: the progress of leaching can be described by … Read more
The National Energy Strategy (NES) and the Clean Air Act Amendments (CAA) of 1990 are examples of the nation’s commitment to a clean environment. The need to utilize our energy resources in an environmentally sound manner presents critical challenges and opportunities for coal preparation during the next decade, particularly regarding the control of SO2 emissions. … Read more
Full Scale Test Circuit Based upon the results of the pilot plant test work, a decision was made to conduct a full scale test in 1990 utilizing one of the ten (10) primary mill lines at the National Steel Pellet Plant. Primary Mill Line No. 10 would be converted to a fully autogenous grinding mill … Read more
On-line coarse particle size analyzers can be used in crushing circuits to monitor ore size distribution of both feed and product streams. Fast and accurate information concerning these particle size distributions can improve the efficiency and lower crushing costs. There are several coarse particle on-line size analyzers commercially available, but most of them suffer from … Read more
Hydrostatic trunnion bearings were recently provided on large Semi-Autogenous Grinding (SAG) mills driven by wraparound motors assembled on the head to shell flanges. A conventional SAG mill would have a ring gear driven through one or two pinions. The effects of the magnetic air gap forces from this new SAG mill drive arrangement on the … Read more
The Bagdad mill, built in 1977, was designed for a mill capacity of 36,300 tpd. An ABC (Autogenous Mill-Ball Mill-Crusher) grinding circuit was chosen. The original mill contained three completely independent grinding circuits, each containing one 9.75 m diameter by 3.96 m long fixed speed autogenous mill, one 4.72 m diameter by 6.71 m long … Read more
Improve the strength and other properties of steel alloys. Approach Research by the U.S. Bureau of Mines indicates that steels melted and solidified under high nitrogen pressure acquire yield and tensile strengths that are up to four times the strengths of comparable stainless steel alloys without nitrogen. Fatigue strength, creep strength, and other mechanical properties … Read more
Develop new technology to encourage domestic processing of automobile catalytic converters for recovering platinum-group metals. Background Automobile catalytic converters are used to convert pollutants in automobile exhaust into water vapor, carbon dioxide, and nitrogen. About 1 million troy ounces of platinum-group metals arc used each year in the United States to manufacture catalytic converter. It … Read more
Investigate and demonstrate the possible use of low-density (45-lb/ft³) foam concrete for sealing abandoned mine openings. Although foam concrete has been used in the construction and geotechnical industries tor some decades, it has not previously been used in abandoned mine shaft reclamation. Approach A structurally engineered permanent mine seal for an abandoned coal mine shaft, … Read more