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By L. L. Anderson

Western bituminous coal can be processed to low sulfur liquid fuels by fast reactions. A process (LEFCO) under development at the University of Utah uses coal and catalyst under hydrogen pressure to convert 60 to 70 percent of the coal matter to fuel liquids and gases. Coals have been processed in small diameter (less than 1/2 inch) tubes and at reaction residence times of less than 10 seconds. Effects of process variables on the yield and quality of products have been studied. General features of the process and the properties and characteristics of the products produced are presented. Special features of the process that distinguish it from other liquefaction processes under development are also discussed.

Jan 1, 1975

By Robert W. Elayer

For the design of a coal mine and process plant, a comprehensive foundation of geologic information is essential. Historically, the development, collation, and use of this information for design have been costly and time consuming. With the application of a digital computer, however, the effort expended can be reduced and maximum effective use of the geologic information realized. The purpose of this paper is to demonstrate the feasibility and convenience of using a computer to Store and manipulate geologic data for use in mine and process plant design.

Jan 1, 1975

By Robert M. Doerr

A method, based on radial distribution analysis, was developed for determining the effect of size to which a given ore is broken on the potential recovery in beneficiations targeted to selected concentrate grades. A measuring microscope and computer analysis are used to obtain the radial distribution of the valuable component in polished sections of ore.

Jan 1, 1975

By D. R. Kelland

A program has been carried out over the last two years to apply the technology of High Gradient Magnetic Separation (HGMS) to the problem of mineral beneficiation and specifically oxidized taconite iron ores. This program, supported by the RANN division of the National Science Foundation, has consisted of a laboratory program at the Francis Bitter National Magnet Lab- oratory at MIT and a pilot investigation at the Hanna Mining Company Research Laboratory. 1 The laboratory tests were conducted using several batch type high gradient separators and a continuous separator with a rotating matrix which was constructed at the beginning of the program. The high field magnets available at F.B.N.M.L. were used for investigations above 10 kG but most of the test work was performed in the range of this field value. Ore samples were contributed by several iron ore companies and consisted of oxidized taconites having goethite and hematite as their principal components.

Jan 1, 1975

By R. V. Ramani, V. T. Burgos, J. A. McClay

Summary Cost models have, long been confined to the accumulation and analysis of static-data.. While historical and time study data are valuable for control of existing operations, for new systems and equipment, and for projections, they need to be adjusted or modified. The availability of computer-oriented systems simulators provide yet another method for costing these systems and equipment. This investigation has introduced a concept whereby continuous, variable data can be assimilated and analyzed through the combination of an economic analysis model, which includes a direct costing capability, with a systems simulator. This tandem operation permits increased flexibility and greater atten¬tion to detail in the evaluation of mining systems. The direct costing process is carried throughout the majority of the model operations. Labor and capital costs may be computed directly, even in the absence of the systems simulator, while operating costs re¬quire input parameters, at present, from the subsystems of the Master Design Simulator. Since the costs computed are based on the perfor¬mance of each individual machine unit, the model may be used to evaluate equipment compatibility, system interaction at the mining face, and the effect of system elements on total mining costs. Additional applications of the cost model include the following: 1. Complete mining systems may be evaluated, over their economic life, to determine the feasibility of a profitable operation. 2. Costs associated with mining various segments of the coal deposit may be computed as a guide to planning the mine layout and scheduling the sequence of operations or acquisition of new

Jan 1, 1975

By S. Chander, D. W. Fuerstenau

The inherently sluggish nature of the reactions involving sulfide minerals, particularly molybdenite, in aqueous solutions under ambient flotation conditions make their investigation complicated and difficult. Since the physicochemical nature of sulfides is known to be controlled by electrochemical reactions, a number of attempts have been made in the past to study sulfide mineral-collector interactions through rest potential and electrode polarization measurements. The purpose of the present investigation was to study the interaction of potassium diethyldithiophosphate (KDTP) with molybdenite. In the present investigation of the interaction of KDTP at the molydenite surface, molybdenite electrode rest potential measurements and electrode polarization behavior were experimentally determined under various solution conditions. The standard reduction potential for the equilibrium between dithiophosphate ions (DTP-) and bis(diethoxythiophosphoryl)disulfide (DTP) [(DTP). + 2e :i7-± 2DTP- (1)] can be evaluated from the electrode rest potential measurements on a platinum electrode in deoxygenated KDTP solutions saturated with freshly prepared (DTP)2. Experimental A platinum wire was used as the electrode for potential measurements. Prior to each measurement the elec-

Jan 1, 1975

By H. E. Powell

Over 5 million lb of chromium, 1 million lb of nickel, and 90,000 lb of molybdenum are lost annually in the dusts generated in the production of stain-less steel. Additional losses of these metals in the form of mill scale and grinding swarf may be double the dust losses. This Bureau of Mines report describes a process for recovering these and other metals in the form of an alloy steel suitable for recycling. Zinc and lead, when present in the wastes, are recovered as byproducts in the form of oxide fumes. The laboratory-scale process (10-to 25-lb charges) recovers up to 95 pct of the chromium, 100 pct of the nickel, and 100 pct of the iron. The resultant alloy contains from 10 to 20 pct chromium, 6 to 12 pct nickel, and 55 to 65 pct iron, with lesser amounts of molybdenum and manganese. The alloy is essentially free of zinc, lead, and sulfur. The zinc-lead fume obtained from the treatment contains about 40 pct zinc and 20 pct lead and represents essentially complete recovery of these metals.

Jan 1, 1975

During the 22 years that Isa Mine has been formally involved in accident prevention, it has succeeded in reducing its lost time injury frequency rate by 70 per cent. At present its performance compares very favourably with that of other heavy industries and in particular that of other underground metalliferous mines. When reductions such as this are recorded, people want to know how it is achieved. No doubt it is assumed that if an organisation can maintain a consistent performance in accident reduction, it must have developed a panacea for the prevention of industrial injuries. This assumption would not be in accordance with the facts in the case of Isa Mine which has achieved its record through plain hard work and plenty of it.

Jan 1, 1975

By J. R. Cobble

The Federal Bureau of Mines conducted static tests at 2,500° F on 39 refractory compositions, and dynamic tests at [2,825°35° F] on 31 commercial refractory brick specimens to determine their resistance to corrosion and erosion by a slag similar in composition to that used in producing insulating mineral wool. The static tests showed fireclay, low-alumina compositions (<70 percent A1203), zircon, zirconia, SiC, and clay-bonded graphite refractories to be unsuitable. Dynamic test results indicated that magnesia and chromia compositions were superior to high-alumina compositions (=70 percent A1203) as a furnace lining for melting mineral wool. Data from these tests indicated that magnesia and chromia compositions with low RO/R203 mole ratios were more resis tant to attack by mineral wool slags than ones with high RO/R203 mole ratios.

Jan 1, 1975

By Thomas E. Ban

The continuous sintering process was invented more than 60 years ago by two metallurgists, Arthur S. Dwight and Richard L. Lloyd, who saw a need for automation in mineral processing. Their specific objective was to beneficiate copper ore by desulfurizing and agglomerating it for copper blast furnace smelting at the Cananea plant in Mexico1. Since their early development the process expanded widely in scope, size, and application. The current worldwide sintering applications exceed 250 million tons per year for agglomerating ores of lead, manganese, zinc, and iron. Sintering is also widely used for production of sintered lightweight aggregate from clays, shales, and fly ash. The continuous sintering process took on wide expansion during the 1960&apos;s in foreign countries. Plants for production of approximately 135 million tons per year were built in these countries for sintering iron ore fines as shipped from new iron ore projects of Canada, Liberia, India, Brazil, and Australia. This expansion represented construction of approximately 80 new sintering plants, some as large as 15 thousand tons per day production on a single large sintering machine. Sized self-fluxing or highly fluxed sinter has become recognized as a premium blast furnace charge and has enabled blast furnaces of Japan and Europe to produce upwards of 10,000 tons of metal per day with coke rates less than 1,000 pounds per ton of metal. This coke requirement is practically 50 percent of the ordinary rates achieved during the early 1950&apos;s when the peak blast furnace production was less than 113 of the current records.

Jan 1, 1975

By Seth C. Schaefer

The Bureau of Mines studied thermodynamic properties of Al-Ni alloys con¬taining 0.54 to 30.04 atomic percent nickel with the aid of the high-temperature galvanic cell Al(1) // Al+3 (AlCl3 in NaCI.KC1) // Al-Ni alloy (1 or s). Activities of aluminum and nickel (compared with pure liquid metals as the standard state) show pronounced negative deviation from Raoult&apos;s law at 1,273 K. The properties [?G, ?Gxs, ?G ideal, ?GA1, AGxs1, ?Gni , and ?GNixs] have been derived from the experimental data and are summarized in tables and illustrations. At 1,127 K, the thermodynamic stability for the invariant three-phase equilibrium consisting of a saturated liquid, A13Ni, and A13Ni2 has been uniquely defined by an activity for aluminum of 0.751. A free energy of formation at 1,127 K of -7,940 cal/g-atom was derived for the compound A13Ni.

Jan 1, 1975

By Richard J. Leary

The inputs of capital and labor to support future iron ore production were developed by the Bureau of Mines from projections of iron demand and estimates of capital and labor requirements. Trends in technologic change and the organization of production were analyzed. Labor requirement schedules for iron ore mining and beneficiating were constructed from aggregate inter-temporal trends and 1970 cross-sectional analysis of mines and mills. A sup-ply schedule of the capital requirement for mine-mill-pellet plants was developed from U.S. and Canadian experience. The structure of demand for iron to the year 2000 was examined as well as the availability of resources. Projections of capital and labor requirements to 2000 were constructed under two international patterns of iron ore supply to the United States. The most likely model is for a continuation of the 70 percent United States-30 percent foreign shares, expanding at an average 2.0 percent growth rate to 2000, and supported by a cumulative gross capital investment of $3.8 billion constant 1967 dollars and a labor force in the United States of 29,800 by 2000. The information content of projections is discussed, and the possible effects of international forces on supply are considered. A generalized methodology for estimating capital and labor requirements in other mineral industries also is included.

Jan 1, 1975

Jan 1, 1975

By Robert W. Freedman

As part of a continuing effort to reduce the weight and bulk of equipment that mining personnel must carry underground, the Bureau of Mines and the Mining Enforcement and Safety Administration (MESA) investigated accurate and convenient gas samplers for use by mine inspectors in sampling mine atmospheres. The samplers are septum-stoppered glass vials commonly used for routine blood sampling. These lightweight, compact samplers yield results comparable with those obtained with conventional bottle samplers of 250-ml nominal capacity.

Jan 1, 1975

By Alexander May

The Bureau of Mines, in cooperation with the Florida phosphate mining industry, investigated the dewatering of waste phosphatic slimes. Part of this investigation was to determine the electrophoretic mobilities and cation exchange capacities of the slimes. The mobilities and exchange capacities are reported for samples of slimes taken from 15 plants operating in the Florida land-pebble phosphate district that includes Polk,Hillsborough, Manatee, Hardee, and DeSoto Counties. The electrophoretic mobilities determined were all negative, ranging from -0.24 to -1.93 (micrometers per second) per (volt per centimeter). Also reported are frequency distributions of electrophoretic mobilities, electrophoretic mobilities of slime diluted with distilled water and electrophoretic mobilities of sand-slime mixtures. The cation exchange capacities ranged from 17 to 45 milliequivalents per 100 grams of slime solids.

Jan 1, 1975

By Hatcher MI

Exploration undertaken at Copley diapir has located several occurrences of oxidized supergene and primary sulphide copper mineralization at the margin of the diapir or in adjacent country rocks. The mineraliza- tion is related to carbonate-rich epigenetic solutions which moved along major structural features closely associated with the intru sive diapir.

Jan 1, 1975

By Gilbert DJ, Lemon NM

A case history of a two year study of low grade ores in the Middleback Range area with the objective of defining possible areas of interest from a combination of geological- petrological-metallurgical criteria. Covering the general geology of the area and ore types; the results of metallurgical testwork and the pattern of evolution of these tests; the petrological explanation of the results of the testwork; the culmination of the work in the selection of areas of best potential for more intensive work. Jaspilites consisting of magnetite, hematite and limonite with quartz and silicate-carbonate-sulphide minerals are hosts to high grade iron mineralisation but also constitute a large low grade iron Reserve.

Jan 1, 1975

By Stewart R. Wallace

"For his achievements in unravelling the complex geology of the Climax ore body; for his leadership in the discovery of the Henderson deposit; for his continued encouragement of young geologists; and for his lecture . .."

Jan 1, 1975

By Bradley V. Johnson

The Bureau of Mines constructed a microminer--a scaled-down (5-by 5- by 11-foot) continuous-mining machine of the drum type with a unique triaxially controlled head--for use in a research program to study the effects of continuous-mining-machine parameters on the generation of respirable dust. This report describes field research with the microminer at the Bureau&apos;s Experimental Mine at Bruceton, Pa. Experiments were conducted to determine the effects of depth of cut, rotational speed, and sump and shear rates on the generation of respirable dust. The cutting forces were also monitored and compared with depth of cut. There appears to be a reduction in the amount of respirable dust generated when the depth of cut is increased or rotational is speed lowered, Variation of other machine parameters seems to have little effect on dust generation.

Jan 1, 1975

By Gary Beerkircher

The mine hoisting equipment that is selected and installed at a mine is the lifeline of the mine, and therefore the proper selection of equipment will save a lot of time and money during the life of the mine. Various types of mine hoist designs &e available today, and each has their advantages and disadvantages. Double Drum Hoists, Single Drum Hoists, Friction Hoists and various special designs of these are available but should only be used on applications where they are suitable. There have been several new drive systems for mine hoists which have come into the picture in the last ten years, and they in turn must be evaluated along with the existing drive systems for each hoist application. It does not make sense to properly select the hoist mechanicals, and then have a drive system that turns out to be a bottleneck. This paper will attempt to cover the above noted systems - both the hoist selection and hoist drive system that will provide the mine with a reliable and economical hoisting system. I. Mine Hoist Types There are two basic types of mine hoists available in the world today: the drum hoist on which the hoist rope is actually stored during the hoisting cycle, and the friction (Koepe), which merely passes the rope over the wheel during the hoisting process. Following is a general outline of each type of hoist and the hoisting applications that they are suitable for. First let us consider the simple Single Drum Hoist. As a Service or Production Hoist with cage or skip in balance with a counterweight, a Single Drum Hoist can efficiently service one or more levels since the location of the counterweight at anytime is not important. As a Production Hoist with skips in balance the Single Drum Hoist is best used for single level hoisting. All rope adjustments for proper spotting must be done manually for the Single Drum Hoist. This has to be done periodically to compensate for rope stretch. A variation of the Single Drum Hoist is the divided drum hoist. If multi-layer winding is necessary the Single Drum Hoist must have a divider to allow a separate compartment for each rope. If a counterweight is used with a divided drum application the counterweight rope can be wound on a smaller diameter (Figure 2). Consequently, it moves a lesser distance than the main conveyance and rope adjustment problems are reduced.

Jan 1, 1975