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By Charles H. Grant

Blast design methods generally deal with end points or limits of design such as spacing, burden, stemming depth, etc. Even cratering design deals with limits defined as a function of energy decay to a limit. Although this crater method provides a better method than trial and error judgment it does not take into consideration the distribution of energy throughout the material to be blasted. This paper deals with a method of examining this distribution with the aid of a computer and how changes in blast design affect this distribution. First I would like to explain the equation used to develop the energy summations throughout the blast. As shown in Figure I a series of drill holes are drilled to various depths starting by placing the explosive charge on the surface and then at various depths until a sufficient depth of hole is reached to exceed the ability of the explosive energy effect to reach the surface of the ground. All volumes of explosive are the same, all holes contain the same explosive and the drill hole diameter is the same.

Jan 1, 1980

By John W. Harshbarger

The Upper Santa Cruz Groundwater Basin lies in the drainage area of the Santa Cruz River in Arizona, and extends upstream from the community of Rillito to the international boundary, see Figure 1. The principal water use area lies between and includes the cities of Tucson and Nogales. A subsurface geologic barrier near Rillito provides a reasonable dividing line between the groundwaters of the Upper and Lower Santa Cruz Basins. The Upper Basin contains the Tucson and Sahuarita-Continental critical ground- water areas. The Tucson Water Use Area encompasses the Tucson metropolitan area and extends from the northern boundary of the Basin south to the boundary between the Tucson and Sahuarita- Continental critical groundwater areas near San Xavier. The San Xavier Use Area is the San Xavier Indian Reservation. The north and south boundaries of the Continental Use Area coincide with the limits of the Sahuarita-Continental critical groundwater area. The first study of groundwater in this valley was initiated by Dr. G. E. P. Smith in 1905 and the results were published in 1910, followed by a series of bulletins of the Arizona Agricultural Experiment Station, University of Arizona, covering the general field of groundwater development and utilization. Beginning in 1939, the Ground Water Branch of the United States Geologic Survey, in cooperation with the Arizona State Land Department and the Arizona Water Commission (AWC), have published a series of bulletins concerning groundwater occurrence and utilization in various areas of the state. In 1975 and 1977, the AWC published the "Arizona State Water Plan" (1), comprising a detailed inventory of water availability and use in the State of Arizona, and a study of alternative futures.

Jan 1, 1979

By B. Nyman

A lot of work is in progress to improve copper recovery by leaching-solvent extraction-electrowinning (L-SX-EW). At Outokumpu the focus of attention is on SX equipment development as a result of which a new mixing-settling technology, the Vertical Smooth Flow (VSF) has been introduced. Using helical stirrers in the VSF mixers a more gentle and uniform contacting can be obtained than in the mixing compartments of the low-profile design. The benefits of Outokumpu's new approach are an essential decrease in organic losses and in aqueous in organic entrainments. Separate pumping using a smoothly pre-contacting "Dispersion Overflow Pump" (DOP) is a key feature of the VSF design. The scale-up of this pump as well as the VSF mixers are shown to follow simple mathematical relationships which also have been confirmed by full scale experiments.

Jan 1, 1995

By D. R. Hembree

This paper discusses the mineralogy and metallurgy of the Kuroko-style volcanogenic massive sulfide ores mined at Formosa Exploration Inc. I s Silver Butte Mine located in southwest Oregon. The principle ore type is pyrite + chalcopyrite + sphalerite, while subsidiary pyrite + bornite + sphalerite ore is also mined. The two styles of mineralization have distinctly different metallurgical behaviors and must be treated separately. Selective flotation methods are used to produce copper and zinc concentrates from the first ore type, while bulk concentrates are produced from the bornite ore. Careful mine planning and coordination between the mine and mill are utilized to achieve optimal recoveries.

Jan 1, 1993

Continuous improvement has become the watchword of the 1990s for most iron-ore-processing operations. In many instances, this improvement has been achieved through stepwise application of advanced control techniques to optimize operations. The benefits of this stepwise application have been great. However, they have fallen short of the full potential offered by the prospect of overall plant optimization. The successful integration of computers, instrumentation and control software throughout a plant promises to deliver an additional 3% to 5% of productivity in even the best-run plants (Herbst and Bascur, 1984). LKAB is Europe's largest iron-ore producer and a leading implementer of advanced control technology. In the late 1980s, LKAB introduced advanced control in its concentrator at Kiruna, Sweden to improve plant performance through higher productivity, greater efficiency and lower costs at each processing step.

Jan 1, 1995

By Bart Hogeweg

The development of deep sea mineral deposits creates a new horizon for the mining industry. In a field where mining technology meets deep-water offshore engineering, new challenges are faced to come to the successful exploitation of these deposits. With the absence of proven technology for the mining of these minerals, a ?technological green field? is entered. IHC Merwede (IHC), a global market leader in the dredging and wet mining industry, is on the frontline of these developments. MTI Holland, IHC Merwede?s research and development company, has undertaken a number research efforts focused on the successful development of technology for the mining of deep sea minerals. This paper highlights a number of these efforts and illustrates IHC?s continued dedication for the research and development of technology to enable the commercial mining of deep sea minerals.

Jan 1, 2008

Land management planning is an important issue in all jurisdictions, especially as it relates to mineral development. These planning documents are prepared at different intervals and reflect the realities at the time that they were prepared. The Seven Questions to Sustainability developed during the North American Process of the Mining, Minerals and Sustainable Development (MMSD) project are proposed for the evaluation of Land Use Plans as they relate to Mineral Development. This paper provides the background to the Seven Questions to Sustainability and how it can be applied to the evaluation of land use plans with specific reference to Resource Management Plans developed by the U. S. Department of the Interior?s Bureau of Land Management in Nevada. While this paper is focused on Nevada, the approach is broadly applicable and may be used in other planning regimes.

Jan 1, 2007

By S. M. Hsiung

This paper presents the results of an extensive study concerning a series of roof falls in a room-and-pillar coal mine located in West Virginia. Three dimensional finite element modeling was employed to identify the possible causes for the roof falls. The effectiveness of possible roof control measures for alleviating or eliminating the adverse roof conditions is analyzed, discussed, and compared. The best mining alternatives are recommended. It has been found that large overburden depth and typical roof geology are the major reasons for the roof falls. Angle bolting may not solve the problem encountered in the mine studied. Changing the mine layout currently used in the mine appears to be the best alternative. The recommended pillar size and entry width which will eliminate the problem completely are 90 ft. x 90 ft. and 14 it., respectively.

Jan 1, 1985

By C. J. Pritchard, R. D. Jacksha, K. V. Raj, C. B. Sunderman

In underground metal/nonmetal mines, repeated localized short-term exposure to high levels of airborne contaminants can become a serious health issue. Currently, there are no common mechanisms to control or mitigate these short-term high exposures to contaminants. To improve miners’ health and safety, the U.S. National Institute for Occupational Safety and Health’s Spokane Mining Research Division (SMRD) is developing a smart monitoring and control (SMAC) system for the real-time monitoring of mine air quality, with integrated countermeasures to reduce high concentrations of airborne contaminants in localized sections of mines. To develop and test a SMAC system capable of being implemented in an underground mine, SMRD researchers built a test apparatus incorporating a fan, louver, ducting and sensors combined with atmospheric monitoring and control software. This system will institute effective countermeasures to reduce contaminant levels, improving miner safety and health.

Jan 1, 2018

By Carl P. Venzke

Mining lignite in the Gulf Coast often requires some interaction with shallow ground water system. Suggestions for determining ground water data and analysis requirements for regulatory compliance are given. Simple methods for estimating mine inflow seepage, ground water level declines, and changes in ground water chemistry, which may result from mining, are discussed. The mining of lignite often results in interaction with shallow ground water systems. An evaluation of the interaction is required as input to mine permitting and engineering. Your evaluation will proceed more smoothly and produce more meaningful results with some planning prior to performing your evaluation. The following are tips to consider in planning and carrying out a successful study.

Jan 1, 1982

By Edward W. Long

The Density Separator is basically a hindered settling classifier with automatic control features that provide steady, sharp classification irrespective of extreme variations in dry tons per hour of feed solids up to the design maximum throughput for the particular material being treated. The size and capacities of commercially available units and operating data comprise the scope of the paper. Applications of the unit for other than classification are proposed, i.e. washing and desliming.

Jan 1, 1982

By Richard D. Grove

The on-stream analysis of phosphorus and silica has not been possible by XRF techniques and only recently has some success been indicated with quantitative XRD for P. Yet there has been a recognized need for an on-stream analysis of P and acid insoluble to permit the automatic control of phosphate rock flotation plants which produce some 30-40 million tons of concentrate each year in the southeastern U.S. IMC Fertilizer, Inc., the largest U.S. phosphate rock producer, embarked on a program to develop such an on-stream analysis capability several years ago. Following many months of lab and prototype development, the first commercial installations started in December 1986 and now have completed some 400,000 analyses with surprising accuracy, precision and reliability. The use of these devices in the improved control of the phosphate flotation plant is currently receiving some very serious attention at IMC.

Jan 1, 1989

By E. Watkins, V. Gangrade, P. Zhang, J. Addis, D. W. H. Su, T. Minoski, C. Hollerich, M. Van Dyke, S. Schatzel, H. Dougherty

"This paper presents the results of a comprehensive study conducted by the Centers for Disease Control (CDC), National Institute for Occupational Safety and Health (NIOSH), Pittsburgh Mining Research Division (PMRD) to evaluate the effects of longwall-induced subsurface deformations and permeability changes on shale gas well integrity and safety under shallow cover. NIOSH researchers selected a study site over a southwestern Pennsylvania coal mine, which extracts 1,500-ft-wide longwall faces under 482 feet of cover. One in-place inclinometer well and three permeability monitoring wells were drilled and installed over a 125-ft by 275-ft centers abutment pillar. In addition to the inclinometer well and monitoring wells, surface subsidence measurements and underground coal pillar pressure measurements were conducted as the first 1,500-ft-wide longwall panel on the south side of the abutment pillar mined by the site.A number of FLAC3D finite difference simulations (Itasca Consulting, 2017) were conducted to estimate surface subsidence, coal pillar pressure increases, and horizontal displacements in the in-place inclinometer (IPI) monitoring well. Comparisons of the FLAC3D finite difference simulation results and the surface, subsurface, and underground instrumentation results show that the measured IPI casing deformations are in reasonable agreement with those predicted by the FLAC3D models, and that the measured surface subsidence and underground pillar pressure are in excellent agreement with those predicted by the 3D models. Measured permeability changes were incorporated into a preliminary calculation to evaluate the effect of a hypothetical shale gas well leak on longwall ventilation. Results from this 2018 research clearly indicate that under shallow cover, the measured horizontal displacements within the abutment pillar are at least one order of magnitude higher than those measured in a 2017 study under deep cover and slightly higher than those measured in a 2014 study under medium cover. This research represents a very important step and initiative in utilizing the knowledge and science obtained from mining research to improve miner and public safety as well as the safety and health of the workers in the oil and gas industries"

Jan 1, 2019

By P. Michael

Proponents of geomorphic mine land reclamation have criticized current reclamation practices in the coal fields of steep-sloped Central Appalachia as too narrowly focused on civil engineering principles and neglectful of the functional and aesthetic benefits of reclaiming mine sites in ways that mimic natural landforms and drainage patterns. They observe that current mining and reclamation practices are radically transforming the mountain-and-valley terrain into gigantic flat plateaus and, in doing so, disrupting the beauty and ecology of the natural landscape. Instead of designing and constructing linear or planar surfaces and unvarying slope gradients during the reclamation process, they recommend ?landforming,? i.e. the adoption of curvilinear, compound slope forms that blend well with the surrounding physiography and represent the result of naturally stabilizing geomomorphic processes. The authors feel that the concept of geomorphic mine land reclamation is sound, however, its application to the Central Appalachian coal fields faces significant--albeit not insurmountable--challenges. They include: (1) existing reclamation enforcement regulations that are focused on civil engineering principles and not explicitly supportive of geomorphic methodologies; (2) regulatory agencies? current intent to limit the down-gradient reach of excess spoil fills in order to allay disruption or burial of natural streams; (3) actual or perceived increases in reclamation costs; and (4) the challenge of designing and constructing ?natural? landforms that are mature and stable in an otherwise youthful, erosional landscape.

Jan 1, 2010

By James Warren Andrews, Philip C. Nyberg

The regulation of exposure of underground personnel to radon and its daughter products has significantly changed since the 1950's. The U.S. Bureau of Mines - Mining Enforcement and Safety Administration (MESA) - Mine Safety and Health Administration (MSHA) sequence of standards and regulations have lowered the maximum allowable occupational exposure and now the new Environmental Protection Agency (EPA) National Emission Standards for Hazardous Air Pollutants, effective in 1990, have further regulated uranium mine emissions. Under the authority of Section 112 of the Clean Air Act (42 U.S.C. 7401), the EPA has set regulations for the control of radon (Rn-222) emissions from underground uranium mines as well as other sources. Since the venting of radon from the mine atmosphere to the outside air is a major component of the miner's protection, and since this is the first quantitative effort to limit gaseous mine emissions to the environment, it was felt that it would be useful to examine the implementation of the EPA regulation at working mines. The concern was not only for determining compliance with the regulation but also for observing what effect the rule might have on mine air quality and thus on worker exposure. The regulation is stated in terms of the maximum permitted radiation dose to the closest potentially exposed individual, which is calculated from a computer program supplied by EPA and radon emission rates measured by the mine operator. Relative proximity to nearby populations determines the allowable magnitude of mine exhaust ventilation emissions. For some mines this is a serious operational constraint.

Jan 1, 1991

By J. W. Stevenson

The need for a separate ventilation department within the management team was recognized by the management of U. S. Pipe and Foundry before the company was purchased by Jim Walter Corporation in January, 1970. Because the coal beds of the deep underground coal properties owned by Jim Walter Resources lay 1300 to 2200 feet below the surface, efficient mine ventilation practices are essential through shaft openings varying from 16 to 22 feet in diameter. The extremely high methane gas quantity indicated to be in the coal bed because of the depth of cover and documented by various U. S. Bureau of Mines tests and demonstrated by early mining proved the need to implement this early management decision. At U. S. Pipe and Foundry mine ventilation was a function of the Mining Engineering Department with ventilation personnel assigned to the mine receiving their day to day work assignments from the mine manager or mine foreman. At Jim Walter Resources, the General Manager - Ventilation reports to the Senior Vice President, Mining Engineering, who reports directly to the President, Mining Division, Figure 1 (Company Organization Chart). Position descriptions are static; however positions are dynamic and consequently the degree of emphasis of specific duties and responsibilities change depending not only upon the aptitude of the individual performing the job but also upon his ability to meet the needs of his supervisors; and ultimately upon his ability to react to the economic forces directing our society. The following describes the duties and responsibilities of the General Manager - Ventilation, Figure 2.

Jan 1, 1980

By X. Cui, H. Ding, J. Wen, Q. Gu

This study is a continuation of previous work designed to further explore the mechanism of the bioleaching of sulfide concentrate at neutral pH by heterotrophic bacteria Bacillus megaterium QM B1551. The concentrate contained 13.2 percent nickel (Ni) and 0.2 percent cobalt (Co), which presented primarily as pentlandite and pyrrhotite. Contact and noncontact bioleaching experiments were conducted with finely ground ore at an initial pH of 6, resulting in 44.7 percent of Ni and 38.2 percent of Co leached in the contact-bioleaching treatment. Oxidation experiments of sulfur, thiosulfate (S2O32−) and ferrous ions (Fe2+) by cell membrane were performed to verify whether sulfur transferase, thiosulfate quinone reductase and enzyme cytochrome B558 on the surface of the bacteria could be expressed to oxidize the sulfide. The results show that thiosulfate quinone reductase and cytochrome B558 could be expressed to oxidize S2O32− and Fe2+ to SO42− and Fe3+, respectively.

By Joseph Cervik

Common methods of controlling gob gas in U.S. nines are by means of ventilation of gob areas and gas drainage through surf ace boreholes. Costs of drilling surface gob holes increase as deeper coalbeds are mined. Where gob holes cannot be drilled because of topography, ventilation is the only means of control. Even then, sufficient air may not be available to dilute methane in the bleeder entries to acceptable levels. Thus, new methods of gob gas control need to be developed that are independent of surface topography, and of the mine ventilation system, and less costly than present systems. Except for slight variations in procedures and equipment, Great Britain, West Germany, France, Belguim, Poland, and Czechoslovakia use a common methane control method that is different from the system generally used in the United States, This Bureau of Mines paper reviews European mining methods, mining conditions, and methane control technology and discusses their applicability to U.S. mines.

Jan 1, 1979

By C. K. Jankousky

The midwestern area referred to is the Illinois basin. The coals presently worked are mainly the No. 5 and No. 6 coal seams which vary in thickness from five to eleven feet. Present average of the more important No. 6 id about nine feet. The coal can vary considerably in toughness within the same mine with some coal perhaps rashing very easily and other coal being extremely difficult to cut. Top is generally well laminated shales with some fortunate areas having limestone roof. There are local areas with troublesome top of poorly laminated shales, shale with slickensides and shale intermingled with small partings and traces of coal. The bottoms are generally one to three feet of clay which softens readily on exposure to moisture. The mines are dry although some water is released and collects from rapid penetration of the seam by continuous miners. However, there are locally wet areas. Most of this material refers to mines of the Freeman Coal Mining Corporation. The mining operations written about are underground mines in southern and central Illinois.

Jan 1, 1962

By R. L. Nielsen

The thematic mapper (TM) aboard Landsat II records image data at seven wavelength intervals or bands. Three record the visible region; three record reflected IR energy. A false color image combining bands 7, 4 and 2 rendered as red, green and blue respectively provides maximum discrimination of rock types in arid regions. Structural analyses and interpretation defines regional structures, large volcano-tectonic features intrusive complexes, all which localize mineralization. Special digital processing using the ratio: Band 3 / Band 1 can identify limonites and other iron minerals. The ratio: Band 5/ Band 7 identifies clays and alunite. These ratio images show features and patterns of hydrothermal mineral systems: ?patterns of sulfide and alteration zoning in large porphyry systems, and zones of strong silica, quartz-alunite-illite, and pyrite-sericite in epithermal centers. Thus, digitally processed Landsat TM images are a cost effective and rapid means to recognize altered areas and define targets for large mineralized systems.

Jan 1, 1995