Search Documents

By N. R. Sainath

This paper discusses the results of a laboratory investigation carried out to study the microscale flow characteristics of copper ores and the variation in flow behavior resulting from flow of leach solution. Fractures in 1.5 and 4 inch diameter cores were mapped by visual inspection. The cores were stressed in a triaxial stress field representative of in situ conditions. The permeability of the samples to water was then estimated. The samples were exposed to 20 g/l sulfuric acid and the experiment repeated. The Permeability of unleached samples ranges from 10-1 to 10-19 m2 and it increases as leaching progresses. The porosity variation and the rate of recovery of copper from the specimen during leaching were also studied.

Jan 1, 1991

By T. B. Szwilski

The paper gives an account of the development of a mine health and safety program in China from 1987 to 1996. The project was funded by the United Nations Development Program and managed by the International Labor Office (ILO). The objective was to strengthen the capability of the National Safety Training Center (NSTC), located near Beijing to train more than 2,000 engineers per year, and provide consulting and informational services to 39 safety training centers and coal mines. Presently China has the highest mortality rate in the world for coal mine operations, the greater incidence occurring at the many thousands of small, unlicensed underground mines.

Jan 1, 1998

By Ralph Spickermann

UK Seabed Resources (UKSR) signed a manganese nodule exploration contract with the International Seabed Authority on 8 February 2013 for a 58,000 km2 tract on the eastern edge of the Clarion Clipperton Zone (CCZ). UKSR is a private company based in the United Kingdom and established primarily to develop the commercial potential of the CCZ deposits. This is the first of many anticipated regulatory, market and technical milestones that are requisite for (1) environmentally responsible commercial scale production of nodule derived metals and (2) generation of revenue through their sale in the global commodities market. This presentation will describe the progress made to date in this effort and an industry-based perspective on the tasks and challenges that may lie ahead.

Sep 1, 2014

By Peter Van deVelde

Many companies in North America because of economic or environmental reasons are considering reprocessing material from their waste ponds. The Japanese have developed highly specialized machines and techniques to reprocess industrial/mining wastes from settling ponds. This paper discusses the techniques and results of applying this technology to North American applications.

Jan 1, 1983

By F. W. Metzger

Coal quality control in mining and mine planning has always been important and has become even more essential in recent years due to environmental considerations. The primary consumers of the sub-bituminous coals found in the Powder River Basin of Wyoming are electric utilities that require low sulfur coals to meet government air quality regulations. Electric generating plants are designed to burn coal of a specific quality, and the supplier of that coal must be able to guarantee shipments within specified quality tolerances. Over the past several years, Exxon Coal USA and, more recently, The Carter Mining Company, a division of Exxon Coal USA have established an evaluation and development program to accurately define the geology and quality of their coal properties. This requires an adequate drill hole density so that detailed correlations of the coal seam and the lithologic sub-units, of the coal seam can be made. These units must be recognizable in the core and also on geophysical logs.

Jan 1, 1981

By William T. Griswold

Few metals or industrial minerals can boast a better growth record over the past fifteen years than the borates. This period of growth occurred before the influence of any large-scale use in plastics or high-energy fuels. These new developments not only provide expanding markets, but the programs related to their development are generating research information that will lead to many other new uses. The most dynamic growth areas for refined products of boron or borates are in the acid, the oxide and the reduced forms, such as the metal and the hydrides. Expanding requirements for these products will modify the emphasis on the use of naturally occurring sodium borates. Any borate from which boron can be economically extracted will become a potentially important ore. This is particularly true of the calcium borate, colemanite. Only one large deposit in the Western World has ever been developed where the principal economic minerals are sodium borates, This factor alone would discourage any exploration program directed solely toward the discovery of these ores; on the other hand, ample exploration opportunities for calcium borates exist in the desert regions of California and Nevada. It is therefore reasonable to restrict a program to this region, in spite of geologically favorable areas in foreign countries such as Turkey, Argentina and Chile.

Jan 1, 1959

By M. Howe

This is a study of the impact of cyanide from mining waste on riparian communities, primarily vegetation, near Whitewood Creek, down-stream from Homestake Gold Mine in Lead, South Dakota. Cyanide is used in gold processing and the effluent, until fairly recently, was discharged directly into Gold Run Creek which empties into Whitewood Creek. Vegetation, soil, and water were collected from four different sites over a six month period, and samples tested for cyanide concentration. Data indicate a relationship between cyanide in soil and its uptake by certain plants, also, that the Homestake cleanup effort has made the stream viable again.

Jan 1, 1983

By M. K. Rizkalla

This paper discusses the time-dependent behaviour of rock when it involves the presence of several layers of rock strata in the vicinity of mine openings, mining in sequences and the placement of backfill. The paper describes numerical techniques which proved useful when such situations are encountered in practice. The model is elastoviscoplastic. At given time stations, short term loading or changes can be made to the creep behavior of the rock. The modelling technique is first described and is followed by simulations of stresses and displacements in a potash mine with the primary objective to demonstrate the effect of such aspects as mining and fill sequences in 3-D. This involves cutting finite elements representing the strip of the mining face and simultaneously filling those elements representing the newly placed fill. The stiffness of the fill varies with the degree of compaction at each point. In this way, the effect of the time of fill placement, the gap between the top of the fill and the back as well as the degree of compaction are simulated. The second example is a 2-D problem simulating the long term effect of backfill, as a material compacting with time, on the settlement of the layers above it as well as the closure of the room.

Jan 1, 1996

By W. H. Strickland

The research reported here characterizes ultrasonic ranging sensors for autonomous navigation on underground mine mobile equipment. Because ultrasonic rangers are inexpensive, have no moving parts, have no lenses to clean, are small and unobtrusive, and can measure distances in dusty environments, they are especially sui ted to underground mi ne environments. The investigation began with laboratory tests of field of view, angle of incidence, intersensor variation, and ranging accuracy of individual rangers and a ring array of 24 sensors. The results showed the sensors have good accuracy and low variability. Additional experiments at AHAX' s Henderson mine Showed the sensors could accurately and reliably measure rib features, convex and concave corners, and drift intersections. The results showed that when used and analyzed properly, the sensor data may be used reliably for underground mobile equipment navigation.

Jan 1, 1990

By W. A. Heitbrink, J. D. Ashley, R. E. Gresh, J. A. Organiscak, A. B. Cecala

Many different types of mobile equipment used in surface coal mining utilize enclosed cabs to protect equipment operators. The overburden removal process is extremely dusty and can cause excessive exposure to respirable dust, especially crystalline silica. After equipment is used for years, many components of the enclosure deteriorate and its effectiveness is greatly reduced. This report discusses a cooperative research study performed on an Ingersoll Rand DM45E surface drill, retrofitted with a new Sigma pressurization and filtration system. Respirable dust concentrations were substantially reduced from 0.64 mg/m3 during pre-testing to 0.05 mg/m3 during post-testing with the new system, representing a 92% reduction in dust levels in the drill cab. This new system appears to be a very well-built and sturdy device, well-suited for the mining industry.

Jan 1, 2002

By X. Wang, Y. Luo

The propensity of coal spontaneous combustion can be evaluated using various laboratory testing methods, such as R70 adiabatic tests, thermal gravimetric analyzer (TGA) tests and critical self-heating temperature (CSHT) methods. Each of the methods has its unique characteristics and index for classifying the propensity of self-ignition of coals. Accountable relationships among the propensity indices of different methods should be established. Using the newly established R70 and TGA testing setups in our ventilation laboratory, samples from U.S. coal mines have been collected and tested. The TGA is a relatively new quantitative method. A test can be conducted in a relatively short time, within about one and a half hours, compared to the adiabatic tests. The temperature and weight of the sample can be measured with high precision and then used to determine the activation energy of the coal, which is a good indicator of the potential for self-heating. Under a specific experimental design, the TGA technique could perform the proximate analysis for determining coal quality parameters (e.g., moisture, volatile matter, fixed carbon and ash content). These parameters can be used in an empirical equation for assessing the potential for coal self-ignition. The trend of activation energies determined using TGA techniques is reasonably consistent with the trend of activation energies determined using adiabatic tests. As a case study, a comparative analysis of these two methods for determining activation energy was made on coal samples collected from Indiana. The kinetics of the spontaneous combustion mechanism has been explained. If the functional groups of a coal such as hydroxyl (-OH), carboxyl (-COOH), methyl (-CH3), etc., activate more easily with a small amount of activation energy at a relatively low temperature, the coal will have a higher potential for self-heating. With the kinetic and coal quality parameters determined by the TGA setup, it has been found that the coal with a low potential for self-ignition has low self-heating rate, a high activation energy and a high minimum self-heating temperature.

Jan 1, 2012

By P. R. Taylor

The ability to process complex precious metal sulfide concentrates containing antimony and arsenic, in an economic and environmentally safe manner, is an important problem facing the mining industry in the united states. Preliminary experiments have been performed to evaluate the possibility of treating a complex sulfide concentrate to recover antimony and precious metals while fixing the arsenic and sulfur as calcium arsenate and calcium sulfate. The process involves the oxidation of the antimony and arsenic minerals in the presence of soda ash (to collect the sulfur dioxide and to keep the antimony and arsenic from forming volatile compounds), the selective leaching of the arsenic from the roast calcine with a heated caustic solution, the precipitation of the arsenic and sulfate with calcium hydroxide and/or calcium chloride, the reduction of the residual antimony (collecting the precious metals), fuming of the metal to form a marketable antimony oxide, and crucible reduction of the residue to obtain a gold and silver dore. Experiments have been performed to evaluate the first stage of this process. Batch experiments were performed using synthetic concentrates of stibnite and arsenopyrite. Variables that were studied included: mixture weight fractions, temperature, gas flow rate, oxygen partial pressure and time. All of the off gas dust and sulfur containing gases were collected and analyzed. The roast solid residue was subjected to arsenic leach tests and the leach solutions were subjected to arsenic and sulfate precipitation tests.

Jan 1, 1993

By Gregg J. Hodges

The Stillwater Mining Company, a partnership of The Pittsburg & Midway Coal Mining Co. and Manville Corporation, began commercial production of flotation concentrates from the western hemispheres' only primary platinum palladium deposit at Nye, Montana in March 1937. In the fall of 1987 an integrated pilot plant testing campaign of electric furnace smelling and oxygen? blown converting confirmed the feasibility of further upgrading to semi? refined matte or 'white metal". In the summer of 1990 the production smelter was brought on-line at Columbus, Montana. This paper describes the technology transfer from the pilot to the production smelter. Emphasis is placed on flowsheet development and the scale factors between the test and production furnaces and gas cleaning plants. The metallurgical results of the pilot plant and of the early months of production of the commercial works are also compared.

Jan 1, 1991

By A. L. Hannaford

Previous production at Spektakel was undertaken during the periods 1854 - 1888 and 1892 - 1901. During this period a total of 41,7 kt of ore grading 32% Cu was hand-sorted from 270 kt to 360 kt of ore mined. Initial open-pit mining was followed by underground mining, access being by means of an inclined shaft to the 85 fathom level. During the period 1946 - 1952 cement copper equivalent to 5,452 kt of blister was produced by leaching of oxidized ore. The Spektakel ore-body branches and coalesces both in plan and in cross-section which accounts for its remarkably complex configuration. Constituent rock-types are andesenite and various varieties of biotite diorite and of ?norite? (biotite-hypersthene diorite). Closely related spatially, and possibly genetically, but predating the above-mentioned basic rocks are bodies of biotite-bearing monzoritic rocks, locally termed shonkinita.

Jan 1, 1981

By M. E. Gershon

Software for coal blending has gained a lot of recent attention as micro-computer programs have come on the market. Some of this software is appropriate and some is not. This paper looks at the types of models being used and points out the strengths and weaknesses of each. Recommendations are then made concerning the level of detail required for these programs, relating this concern to the various ways in which coal companies are using these programs. A checklist of company requirements for these programs and available pro-gram-features provides an aid in matching the program to the company.

Jan 1, 1988

By J. D. McAuliffe

The Homer-Wauseca Mine is operated by the Hanna Mining Company, three miles north of Iron River, Michigan on the Menominee Iron Range. The mine produces 5,300 tons of direct shipping iron ore daily. The present main producing level is at a depth of 1,500 feet below the collar. The ore body continues to a depth of 2,700 feet below the collar, to which depth the modern circular concrete shaft has been completed. A view of the property is shown in Figure #1. This paper is a report on the development of large underground boreholes used initially to conduct stope filling material into inaccessible, mined-out stopes. Later holes were drilled for ventilation raises, for mine drainage, for passageway for power cable, also for the primary breaking point for long hole stoping. Some, which were drilled as ventilation raises, were later stripped to a suitable size for a manway or ladder road. The holes varied in size from 6" to 30" with the present popular, economical working size being 16 1/4", used as a stope fill passage in mined out areas and for ventilation in deeper development. Foremost has been the desire to develop equipment suitable for drilling raises large enough for manways.

Jan 1, 1963

By Ramon LaRusso, Frank Wheby, Richard Acker

Field investigations and office studies were used to develop criteria and cost parameters related to the geologic aspects of the proposed project. These results were employed in optimization of layouts and comparison of alternative schemes, leading to selection of the recommended program. Study of project features included the development of subsurface shafts, tunnels, and mined storage areas, and the utilization of existing surface quarries. These project features were proposed for construction within the bedrock units underlying Chicago. Principal geologic considerations included bedrock structure, stratigraphic sequence of units, rock competence and uniformity, and requirements for aquifer protection. All geologic factors were interrelated with other project considerations such as surface hydrology, hydraulics, and urban setting. Data for analyses was acquired through an exploration program conducted intermittently between 1967 and 1971, in addition to that already available through numerous explorations and well constructions in the project area. The exploration program included seismic surveying, core drilling, geophysical borehole logging, and water pressure testing of boreholes, and water well drilling and testing. Extensive laboratory tests were conducted on core samples. The data formed the basis of studies enabling the formulation of preliminary design and siting criteria resulting in construction cost evaluation.

Jan 1, 1997

By Robert L. Gamble

The world's largest fluidized bed steam generator located at Rivesville, West Virginia is currently undergoing initial operation. This unit is designed to generate 3708 kg/s (300,000 Ib/hr) equivalent to 30 MWe of superheated steam while firing coal in a fluidized bed of limestone. Coal was first fired in this unit in December, 1976 and start up operation is progressing.

Jan 1, 1977

By John P. Hunt

Early disseminated copper mineralization at Quebrada Blanca, Chile, accompanied 38 million year old quartz monzonite stocks and dikes. Early mineralization was followed by hydrothermal mineralization, mineralized breccias, and post-mineral faulting. After supergene leaching and enrichment, Quebrada Blanca was buried under late Tertiary gravels, and then partially re- exposed in Quaternary time. Based on work to date the orebody appears to contain more than one hundred million tons of plus one percent secondarily enriched copper ore, overlying several hundred million tons of protore averaging more than 0.5% copper. A source of industrial water appears to have been located. Pilot scale metallurgical tests, mine planning, and feasibility studies are in progress.

Jan 1, 1981

By H. Walqui, S. K. Kawatra, C. H. N. Jeltema, T. C. Eisele

"The literature contains many cases where the shape of hydrocyclone efficiency curves vary from the ideal “S” shape. These often appear as changes in slope, or inflections. These inflections can be divided into two categories: “coarse” inflections, which are caused by differences in the density of the minerals being separated, and “fine” inflections, for which there are a number of competing hypotheses concerning their cause. The existing literature addresses either the fine inflection or the coarse inflection, but no studies have reported both types of inflection occurring at once in a single hydrocyclone test. This paper presents hydrocyclone results from both in-plant studies and laboratory experiments that show both coarse and fine inflections. The industrial significance of both types of inflections is discussed. Hydrocyclone efficiency curves show the probability of any given particle reporting to the hydrocyclone underflow as a function of its size. Selectivity functions, S(d), are used to represent the fraction of the feed material in size fraction “d” that reports to the hydrocyclone underflow. Plotting this selectivity function against particle size leads to the standard S-shaped efficiency curve shown in Fig. 1. In the “uncorrected” curve, the tail of the curve does not go through 0%, because a portion of the solids are bypassing classification. This happens as a result of their being carried along by the water, and is most important for the finest particles. The curve can be “corrected” based on the fraction of the feed water that reports to the underflow, represented by the bypass fraction, Rf. The corrected curve then normally passes through 0%, as shown in Fig. 1.The act of correcting the curve shifts the value of the d50 size, which is the size that has an equal probability of reporting to either the overflow or to the underflow. Correcting the curve to account for the bypass fraction makes it easier to compare cyclone performance under conditions that cause the quantity of water in the underflow to change, but that do not alter the actual corrected cut size (d50c).The corrected efficiency curve can be expressed closely by equations such as Plitt (1976):"

Jan 1, 2015