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By Y. H. Chia, P. Somasundaran

Carrier flotation of anatase from clay using coarse calcite is investigated, together with relevant basic properties of the system including aggregation and zeta potential, under different chemical and hydrodynamic conditions The roles of carrier sue and amount also are considered Mechanisms responsible for selective aggregation and flotation are reviewed

Jan 1, 1983

By M. Dale Slade, Gordon S. Bird, Robert S. Kelly

Gallium scrap is obtained from many different sources, therefore each lot received has to be evaluated and then processed accordingly. Some of the problem areas are separating small amounts of gallium from large concentrations of iron, eliminating trace amounts of gold, silver, copper, germanium, tin, and zinc from gallium, and having the flexibility to process each lot of scrap individually Following gallium from the raw scrap material to the final seven nines pure product requires stringent quality control and excellent analytical capabilities.

Jan 1, 1983

By James H. TaVoularis, William J. Wiehagen

This paper discusses the application of commercially available microcomputers for assisting trainers in the delivery and evaluation of new hire, refresher, and occupational training. A brief overview of mine training highlights major issues facing the mine training community. The use of computer-based training has a potential for reducing costs and improving the transfer of conventional training to the job.

Jan 1, 1983

By B. W. Madsen

A modified transpiration apparatus was devised by the Bureau of Mines to permit rapid and accurate measure of the vapor transport and vapor diffusion coefficients of antimony sulfide (Sb2S3) and other compounds at temperatures to 1,045 K. The apparatus was equipped with dual condensers and valves to switch the flow of vapor in a fraction of a second from one condenser to the other, thus allowing short-interval sampling under equilibrium conditions. Reliability of the technique was established by measuring the vapor pressure of ZnC12 as a function of temperature and comparing the results with published data. As part of an investigation of the vapor concentrations and species of accessory element sulfides associated with copper and zinc smelting, the apparatus was used to measure the rate of vapor transport and diffusion coefficients of vapor over liquid Sb2S3 as a function of temperature between 870 and 1,045 K. The calculated vapor density was combined with published direct measurements of vapor pressure to calculate the average molecular weight of the gaseous species. Average molecular weight of the vapor in equilibrium with Sb2S3 ranged from 286 to 112 g/mol over the temperature range studied.

Jan 1, 1983

By Raja V. Ramani

The recognition that surface mining need not be viewed as a permanent dedication of the land but rather as a temporary non-renewable use in a series of land uses has caused greater emphasis on the re-use of surface-mined lands. In an effort to develop a procedure for evaluating postmining land use potentials, specific mines in various regions of the U.S. have been studied to determine the extent of current mined-land planning and to discover characteristics that are regional in nature. As part of this investigation, the Indian Head Mine, which is located in Mercer County, North Dakota, has been studied. The Indian Head Mine is presently operated by The North American Coal Corporation -Western Division and has been in operation since 1917 under various ownership. The status of current reclamation and postmining land use planning was reviewed. In addition, the relationship between mine planning and public planning in an area impacted by energy development was investigated. Finally, key factors affecting site potential realization for western surface mines have been identified.

Jan 1, 1983

By D. S. G. Hanson

The Flin Flon Mine has been in production for over fifty years, and current mining is dependent on pillar and remnant recovery. One of the last major blocks of ore, and an important economic entity to the Mine, is the North Main Shaft Pillar. A rock mechanics program was initiated through under' ground instrumentation and other subsequent analyses, to establish the degree of instability as min¬ing progressed. Several studies have been and will be undertaken to evaluate the general stability, and possibly improve the chances of stability during pillar recovery. The North Main Shaft Pillar is immediately bounded by cemented cut and fill supporting rib stopes which inturn are bounded by slag and waste filled stopes. The min¬ing method involves a modified longhole open stoping and slag fil¬ling sequence for each mining block in a general mining upwards scheme.

Jan 1, 1983

By Edgar W. Sawyer

Attapulgite and sepiolite are the clay minerals used to thicken ionically contaminated watzrs in the preparation of drilling fluids. They are nonsweliing clays that can be dispersed and reflocculated by mechanical means to increase the viscosity of fresh water and salt and gypsum contaminated waters. Those gelled in fresh water do not become excessively thick when contaminated with high salt concentrations or polyvalent cations encountered during drilling. Gels formed exhibit thixotropy and yield pseudoplastic rheological behavior due to the particle interactions and mechanical interferences of the flocculated gel structure.

Jan 1, 1983

By Francis Martino

There are numerous techniques and predictive models used by geologists and mining engineers to define coal reserves and plan mines. The traditional reserve estimation methods commonly used include the isopach, triangular, polygonal, inverse-distance weighting, weighted-moving-average, and trend-surface methods. Geostatistically-based estimation techniques are now being examined by many geologists and mine planners as a superior alternative to these traditional methods. With today's coal mine development costs often exceeding $100 million, and power generation $1 billion, it is logical that a technique that can indicate the degree of confidence associated with a reserve estimate (fuel supply), and thus also the degree of risk, is highly desirable to the coal producer, the financiers, and those desiring to commit to coal utilization under short or long-term supply arrangements.

Jan 1, 1983

By S. J. Schatzel, J. Cervik, A. A. Campoli

The cross-measure borehole technique is being studied by the Bureau of Mines as an alternative to the use of surface gob boreholes as a means of controlling methane in gobs during longwall mining. Small-diameter holes are drilled from underground locations into strata overlying the mined coalbed. When the roof strata are fractured by the mining opera- tion, a partial vacuum applied to the boreholes draws the methane out of the fractured strata and prevents it from entering the mine ventilation system. Tests in the Upper Kittanning Coalbed showed that 50 pct of the methane produced by the longwall mining operation was captured by the cross-measure boreholes. Borehole inclination and penetration into the gob are two important borehole parameters that affect the performance of the cross-measure borehole system.

Jan 1, 1983

By James L. Eirls

Tracor MBA under a contract to U.S. DOI Bureau of Mines designed, developed, fabricated and demonstrated a conveyor belt service machine. It is self-contained, battery powered, rubber tired and capable of handling, storing and transporting conveyor belting, wire rope and associated structures for sectional conveyor belts. While moving the tail section to its next position the machine discharges the belting, wire rope and belt structures. The belting is elevated and separated to provide for the insertion of the structures with minimum expended effort. A hydraulic system provides the power for steering, braking, winding or unwinding under controlled tension the belting and wire rope, operating a load-bed slat conveyor, raising, lowering and locking connection hitches and powering external hydraulic tools. Also, a pneumatic system is available to operate air impact tools. The service machine, with its present components can function in coal seams as thin as 48 inches, double wind conveyor belting 42 inches wide, 400 feet long, load or unload 3/4" wire rope on two separate reels and is controlled by two operators. A complete belt move using this machine requires only four workers. Successful underground demonstrations were conducted in coal mines located in West Virginia and Kentucky.

Jan 1, 1983

By David L. Martin

This paper discusses the development of a SLAM II* simulation model with imbedded optimization modules designed M evaluate mineral exploration and exploitation strategies. The model traces through a sequential exploration program, evaluating each deposit site based upon geologic information and potential profitability of the site. At a specified time during the simulation, a new production plan is developed for currently producing deposits which takes into account the planning horizon and deposits which are currently being explored. Potential uses of the model by geologists, engineers, and management decision makers include setting corporate objectives and policies on exploration and production. The model is also useful for testing past decisions to evaluate decision making criteria and evaluating mineral deposit profit potential.

Jan 1, 1983

By R. L. Shaw, D. W. Alexander

Consolidation Coal Company's Loveridge Mine operates the only coarse coal hoisting and overland slurry transport system in North America. The system has been in operation since April 1980 and according to current haulage levels will have handled over two million tons by this conference date. Original performance goals have been exceeded. The systems will be described and their application to rapid excavation and tunneling haulage needs will be discussed. Manuscript not received in time for publication.

Jan 1, 1983

By T. Skodack

This presentation will compare actual work site results for the loading and transport of shot rock for two major tunneling projects in North America. "SCARMAR" (the Canadian subsidiary of S & M Construction) is operating a rail bound Hagglund continuous gathering arm loader in combination with a Hagglund nine car shuttletrain system at the West End of Table Mountain on the B.C. Railway project near Tumbler Ridge, Canada. Al Johnson Construction is operating a Hagglund rubber tired continuous gathering arm loader in combination with haul trucks at the Rocky Mountain Pump Storage Project near Rome, GA. This paper will compare: 1) tunnel and ground conditions, 2) the total work cycle as it relates to mucking and haulage 3) efficiencies and related problems with the two systems 4) mucking and haulage rates 5) operating costs, and 6) recommendations for future large tunnel excavations. Manuscript not received in time for publication.

Jan 1, 1983

By Lung Cheng

Based on earlier tests that showed steel to be much more likely to cause frictional ignition than tungsten carbide, the Bureau of Mines redesigned coal-cutting bits to reduce the hazard of face ignitions. Two bit designs--a mushroom-shaped bit with a conical shank and a dove-tail bit with a rectangular shank--are described, as well as bit wear tests conducted in the laboratory and in an operating coal mine. In laboratory tests, for 1/8-, 1/4-, and 1/2-in-deep cuts and cutting speeds of 280, 500, and 660 ft/min, the mushroom bit had significantly longer tip wear life than the conventional bit; the dovetail bit was also superior to the conventional bit. Results of in-mine tests on the mushroom bit agree well with laboratory results. In-mine tests of the dovetail bit are underway.

Jan 1, 1983

By Wayne Anderson

Regarding the technical paper by Thomas E. Finch and Edward L. Fidler, "Recovery of Stray (Thin) Seams in Western Coal Mining." I would like to comment on this subject. In western Canada, most strip mines encounter thin seam coal or rider seams. Although the paper addresses the problems and costs associated with the recovery of this coal, it does not take into account what the savings are. Without looking at the savings, the "Total Objective" is of course not clear. I feel that in a stripping operation the mine can spend per ton (of the thin seam) up to their dragline stripping costs per ton to recover a rider seam or thin seam. The reasoning behind this is simply that this is the price the mine will have to pay to expose an equivalent amount of coal without the recovery of these thin seams. If the mine can recover a rider seam or thin seam for less than the dragline operating costs per ton, a savings will be realized. By recovering a thin seam or rider seam, the life of an ore body is extended by that amount of coal not thrown away. In addition, the cost of land acquisition, associated permits, capital, and reclamation will be reduced as more coal is delivered for a given area. When the above points are considered, the recovery of these thin seams can be very profitable and indeed worth recovering.

Jan 1, 1983

The causes and impact of stability problems associated with longhole open stoping (LHOS) at The Zinc Corporation, Limited (ZC) and New Broken Hill Consolidated Limited (NBHC) are discussed and LHOS stability objectives presented. The development of appropriate rock mechanics techniques is discussed and the reasons for using contract research are explained. Reference is made to the rock mechanics techniques developed and in use. The requirements to effectively use these techniques are discussed. Features of the staffing policy which has been adopted to develop and apply the LHOS stability assessment and control techniques are Outlined.

Jan 1, 1983

By R. R. Lowery

An analysis of three 1-1/4-diam manufactured wire ropes of 6x19 classification was done to identify and describe reference conditions of new rope. Reference condition is of value when examining tested or retired ropes. Measurements of strand and rope pitch and of wire and rope diameter confirmed adherence of all ropes to those construction specifications. Mechanical properties of strength and ductility were determined by accepted methods for the ropes and wires from the ropes. Individual wires from one rope failed to meet minimum wire ductility values. Wire chemical composition varied in average carbon levels, from 0.70 to 0.78 wt pct, and in manganese content, from 0.45 to 0.80 wt pct. One manufacturer's product contained 1 to 3 wt pct Ni and Cr. Heavily wrought pearlitic steel microstructures were porous and contained inclusions. Cold work variations were evidenced by wrought grain width. Recorded anomalies reflected the condition of the manu-factured products. The report provides data that compare the three wire ropes studied, but cannot verify the effects that these conditions or anomalies have on rope service life.

Jan 1, 1983

By R. G. Henley

Mount Isa copper concentrate was combusted in a laminar-flow furnace. The conditions simulated those likely to be encountered in flames in flash smelters of the Outokumpu (air as oxidant) and INCO (oxygen as oxidant) types. The range of conditions studied was as follows: T 400-1400°C, 02 0-100%, SO2 0-95% for residence times up to 0.23 s. The distribution of sulfur, arsenic and lead between the particles and the gas phase was studied. Combustion was very rapid provided the concentrate was adequately dispersed, i.e., no agglomerates. The importance of the latter is discussed. It was possible to oxidize 80% of the sulfur present in the con¬centrate after only 0.1 s reaction time at 1000°C in an atmosphere contain¬ing 8.5% 02 and 12.5% SO2. Best volatilizations (90% of the As, 52% of the Pb) were obtained under localized conditions attained in an air-type flame. Average volatilizations were: air-type flame, As 50%, Pb 32%; oxygen-type flame, As 40%, Pb 30%. The substitution of oxygen for air reduced the arsenic volatilization. The products of combustion were mainly cuprospinel and cuprite; small inclusions of elemental copper were found in some of the particles. At high temperatures, there was a loss of copper due to vaporization of CU( g) CuO kg) (g)

Jan 1, 1983

By Hughes DC

Coal development in New South Wales can involve a complex series of government approvals, a requirement that results from the coincidence of many development sites with environmentally sensitive areas. The concept of network analysis is applied to the pre- development regulatory procedures leading up to the grant of a coal lease. The network facilitates a quantitative and qualitative analysis of activity schedules relating to pre- requisite statutory approvals. The sequencing of activities (with clear start and finish nodes, identification of sensitivities and time estimates for completion of each phase of the network) provides government and industry with an effective planning tool.

Jan 1, 1983

By Barry K. McMahon

Following minor slope failures at the commencement of mining the west wall of the Kanmantoo Mine was redesigned from an overall slope between haul roads of 55° to 46°. This decision was based on a probabilistic analysis which indicated that 46° was the optimum economic slope.

Jan 1, 1983