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By Kevin Andrews, Zach Agioutantis

Analysis of Coal Pillar Stability (ACPS) software, released in 2018, integrates numerous empirical pillar design techniques. The ACPS program incorporates methodologies originally available as design tools from the National Institute for Occupational Safety & Health (NIOSH), including Analysis of Longwall Pillar Stability (ALPS), Analysis of Retreat Mining Pillar Stability (ARMPS), Analysis of Multiple Seam Stability (AMSS), and concepts including Coal Mine Roof Rating (CMRR), the Mark-Bieniawski pillar formula, and pressure arch loading. The design methodologies that are the basis of ACPS were developed via analysis of significant amounts of real-world data and have been standards of the United States coal industry for decades. While there are empirical factors built into ACPS, making it ideal for use in U.S. coalfields, the concepts in the program have proven to be applicable in variable mine settings, and the software was developed to allow for user-based, site-specific modifications of key design inputs. Application of ACPS to cases outside the regions for which it was developed must be approached carefully, and continuous development of site-specific data is mandatory. A case study is presented involving the application of ACPS to assess pillar stability and assist future design for an underground lignite mine in Eastern Europe. Assessment of in-mine observations, review of the geology of the lignite mine, and evaluation of specific conditions associated with a failure event resulted in “calibration” of key input factors to ACPS. Scenarios evaluated with ACPS suggest that pillar strength and overburden depth are key factors for the determination of pillar stability and design in future areas.

Jun 25, 2024

By R. M. Rowe, T. E. Irwin

A flowsheet was developed for upgrading Climax tin concentrate to about 45 percent Sn. Bench-scale test work conducted at AMAX Extractive Research and Development, Inc., was used to design a multiple-stage tin- processing flowsheet which included screening, high-intensity magnetic separation, and high- tension (electric- static) separation. Formal engineering and plant installation was accomplished in-house by Climax mill personnel. The successful start-up operation of the facility was the joint effort of the AMAX R&D and Climax-mill staffs.

Jan 1, 1986

By M. Raffaldi, J. Johnson, M. Stepan, D. Benton

"The Office of Mine Safety and Health Research (OMSHR), Spokane Mining Research Division (SMRD), is continuing its High-Energy High-Displacement (HEHD) testing of field-scale shotcrete panels. A test program was developed to determine the relationship between applied force, displacement, and energy for both unreinforced and reinforced shotcrete panels. Reinforcement options consisted of synthetic macro-fibers, sprayed polyurea liners, chain-link fence, welded-wire mesh, and combinations of these products. During testing, photogrammetry was used to measure the geometric changes of the panels, including volume changes and panel cracking. These measurements were correlated with the load and displacement data, allowing visual observation to be related to the applied force and displacement. The test results provide a comparison of the mechanical performance of the various panel types and can be used by the practicing engineer to evaluate installed support based on visual observation of cracking and deformation. Visual assessment of the loading cycle and strength capacity of shotcrete in underground excavations will improve mine safety by providing a means to quantify the stability of installed shotcrete support. INTRODUCTION The National Institute for Occupational Safety and Health (NIOSH), Office of Mine Safety and Health Research (OMSHR), Spokane Mining Research Division (SMRD) is continuing research on the behavior of shotcrete when used as the surface support component in mining ground support systems. Ground control safety often depends on supporting, or at least containing, the ground between the rockbolts. Shotcrete and mesh, in various combinations and with other components, are often used to accomplish this (see Figure 1). Maintaining support pressure during ground deformation is key to the performance of these systems, and to ensuring miner safety. However, the toughness of a ground support system–the ability to maintain strength over large deformations–is difficult to quantify. Researchers at SMRD have responded to this deficiency by designing a full-scale test device, described previously by Martin et al. [2015a], and beginning a testing program to assess the behavior of shotcrete surface support reinforced with a variety of products including: fibers, chain-link mesh, welded-wire mesh, spray-on polyurea liners, and combinations of these products. This paper presents the findings of these tests."

Jan 1, 2016

By M. Raffaldi, J. Johnson, M. Stepan, D. Benton

"The Office of Mine Safety and Health Research (OMSHR), Spokane Mining Research Division (SMRD), is continuing its High-Energy High-Displacement (HEHD) testing of field-scale shotcrete panels. A test program was developed to determine the relationship between applied force, displacement, and energy for both unreinforced and reinforced shotcrete panels. Reinforcement options consisted of synthetic macro-fibers, sprayed polyurea liners, chain-link fence, welded-wire mesh, and combinations of these products. During testing, photogrammetry was used to measure the geometric changes of the panels, including volume changes and panel cracking. These measurements were correlated with the load and displacement data, allowing visual observation to be related to the applied force and displacement. The test results provide a comparison of the mechanical performance of the various panel types and can be used by the practicing engineer to evaluate installed support based on visual observation of cracking and deformation. Visual assessment of the loading cycle and strength capacity of shotcrete in underground excavations will improve mine safety by providing a means to quantify the stability of installed shotcrete support. INTRODUCTION The National Institute for Occupational Safety and Health (NIOSH), Office of Mine Safety and Health Research (OMSHR), Spokane Mining Research Division (SMRD) is continuing research on the behavior of shotcrete when used as the surface support component in mining ground support systems. Ground control safety often depends on supporting, or at least containing, the ground between the rockbolts. Shotcrete and mesh, in various combinations and with other components, are often used to accomplish this (Figure 1). Maintaining support pressure during ground deformation is key to the performance of these systems, and to ensuring miner safety. However, the toughness of a ground support system–the ability to maintain strength over large deformations–is difficult to quantify. Researchers at SMRD have responded to this deficiency by designing a full-scale test device, described previously by Martin et al. [2015a], and beginning a testing program to assess the behavior of shotcrete surface support reinforced with a variety of products including: fibers, chain-link mesh, welded-wire mesh, spray-on polyurea liners, and combinations of these products. This paper presents the findings of these tests."

Jan 1, 2016

By Fred D. Wright, Stefan H. Boshkov

12.1-BASIC AND PARAMETRIC CRITERIA IN THE SELECTION, DESIGN AND DEVELOPMENT OF UNDERGROUND MINING SYSTEMS STEFAN H. BOSHKOV AND FRED D. WRIGHT The criteria governing the selection of an underground mining system relate to several factors the importance of which varies with geographic location, the state of development of the industrial technology, the economic climate in the Nation and, perhaps, in the world-all these as functions of time. Thus, the best choice of a mining method depends upon sets of definable and undefinable values for numerous factors that may be considered fixed at the precise point in time. Subsequent changes in economic and/or technological developments may necessitate modification or complete revision of the existing mining system. A classification of criteria for selecting a mining system must be based on the broadest definitions. Specific cases may present simple solutions or pose very intricate questions, the answers to which are frequently based on judgment rather than explicit logically reasoned and derived results. Specific criteria may be of negligible consequence in some instances and of overriding importance in other cases. It would be foolhardy to attempt to point out, in the limited space available, all possible variations and interplay of factors, as well as to define the setting in which this interplay can take place. The reader is, therefore, referred to the case histories described in the subsequent parts of this section where actual practice will point out the variability of the problems encountered in the selection of a mining method. A popular thesis suggests that the proper approach to selecting the method of mining should be rooted in the inverse solution, whereby the limitations of the various methods in use serve as criteria to eliminate most of these methods from consideration in the specific case. This narrows the ultimate selection to one or perhaps two most appropriate methods. At this stage, a critical comparison analysis will lead to the ultimate choice. Although such a negative approach un¬questionably is valid in discarding obviously inapplicable mining systems from consideration, it falls short in defining the best system, which in practice quite often turns out to be a variation of a textbook standard, or a combination of two or more such standards. Because the deployment of capital and manpower over a long-term commitment closely follows the selection of the mining system, the decision-maker can well afford to spend a great deal of time and effort in evolving the optimum solution for the peculiarities of his specific case. Within the basic engineering tenets of economy and safety to which the design of a mining system must adhere lie numerous factors of constraint which may be grouped, somewhat arbitrarily but for ease of discussion, into several categories. The criteria that enter into the choice of a mining method derive from the following groups of factors: 1. The shape, size and spatial position of the ore deposit.

Jan 1, 1973

By Robert D. Harris

In 1958, the coal industry, through Bituminous Coal Research, Inc., and the electric utility industry, through the Edison Electric Institute and the Association of Edison Illuminating Companies, initiated a joint program to study coal pyrite and its removal as a means of lowering the sulfur content of steam coals. It was assumed that significant amounts of pyrite often remained in washed steam coal not because available systems for coal cleaning were inadequate, but because the pyrite was small and widely disseminated, During the first two years, samples of coal were examined petrographically to determine the size, association, and mode of occurrence of the pyrite in the raw coal and in the products of laboratory separation, Samples of coal were also pulverized in different equipment to determine how effectively pyrite was released by pulverization and if the mode of pulverization affected the liberation of pyrite. From these studies, the following tentative conclusions were made (1 ): 1. Much of the coal pyrite is within a 250-70 micron size range, and therefore is too small to be removed by conventional coal cleaning, but relatively large when compared to the size of coal as pulverized for combustion in large boilers. 2. The degree of pyrite liberation is mainly determined by the size of the product and not by the type of crusher. 3. For improved pyrite removal, the coal should be cleaned during or after pulverization at the power station.

Jan 1, 1965

By J. D. Miller

The recent non-equilibrium electro-phoretic mobility measurements by laser-Doppler electrophoresis coupled with the stability and prevalence of collector colloids in soluble salt flotation systems suggest that the selective flotation of alkali halides is due to the adsorption of oppositely charged collector colloids by hetero-coagulation. Previously reported flotation results confirm this surface charge/collector colloid adsorption model. However, the nature of the inter-particle forces responsible for hetero-coagulation of such oppositely charged particles at high ionic strengths remains to be determined. In this regard, atomic force microscopy was used for inter-particle force measurements at high ionic strengths. Model systems such as polystyrene/quartz and silica/sapphire were studied to measure the particle interaction forces prevalent at high ionic strengths. Results from this study indicate that while repulsive hydration forces exist between similarly charged hydrophilic particles, attractive forces exist between oppositely charged hydrophilic particles in high ionic strength solutions. The repulsive forces between similarly charged hydrophilic surfaces at high ionic strengths (2-4 M) are described by a double exponential function with decay lengths of 0.17 and 1.4 nm depending upon the surfaces involved. On the other hand, attractive forces were observed between oppositely charged hydrophilic surfaces at high ionic strengths (2-4M) and were described by a single exponential function with decay lengths of up to 9 nm depending upon the surfaces involved.

Jan 1, 1996

By R. A. Matuszak

Throughout the history of power excavating machines, engineers have continuously tried to shape the main drive speed-torque characteristics to provide an optimum performance from each main motion. Selection of prime mover for the various motions has been the subject of many engineering studies and most forms of energy conversion have been tried. A new form of electrical power conversion looms on the horizon' as the most optimum yet. Controlled frequency operation of a squirrel cage induction motor increases the reliability of the most reliable form of energy conversion (electrical) found thus far and at the same time improves the performance characteristics.

Jan 1, 1977

By R. Kahrger

This paper is written to convey the latest developments in compact bucket wheel excavators (BWE's) operating in medium-hard rock and will serve to indicate that BWE and compact machines in particular do in fact have application in materials other than loose sandy soils and soft rock. A recently run extensive three month field test in hard marl, which was previously considered too hard and difficult to be handled by a BWE, is used as an example to explain some of the design requirements and problems associated with digging harder materials.

Jan 1, 1990

By Kazumasa Taguchi

At the Kakogawa works of Kobe Steel. Ltd., the agglomeration facilities are composed of a pelletizing plant and sintering plant. This aim is to utilize raw materials efficiently and stabilize the raw material resources. Therefore at Kakogawa works, the blast furnaces (BF) have been operated with high pellet ratio and various developments for pellet properties have been achieved to improve the blast furnace performance. These developments include dolomite-fluxed pellets, new-porous pellets and crushed pellets. As a results of these improvements, pellets have achieved almost the same performance as sinter at high temperature regarding properties such as the softening, melting and reduction behaviour. However, some problems on shape have remained to be solved. Spherical pellets flow easily into the center of the furnace and form mixed layers of pellets and cokes. Therefore, in BF operations with these pellets it becomes more difficult to keep proper and stable gas distribution.

Jan 1, 1983

By Van Price

Some technical developments of the National Uranium Resource Evaluation Program which are of general application in geochemical exploration are being studied. Results of stream water and suspended and bottom sediment analyses are compared for an area near Williamsport, Pennsylvania. Variations of uranium content of water samples with time in the North Carolina Piedmont are seen to correlate with rainfall. Ground water samples from coastal and piedmont areas were analyzed for helium. All media sampled provide useful information when properly analyzed and interpreted as part of a total geological analysis of an area.

Jan 1, 1979

By J. Evans

INTRODUCTION Section 209(b) of the Federal Land Policy And Management Act of 1976 (FLPMA-43 U.S.C. 1719 b) authorizes the Secretary of the Interior to convey mineral interests owned by the United States where the surface is or will be in non-Federal ownership. The objective is to allow consolidation of surface and subsurface (mineral) ownership. Certain major conditions must prevail for a conveyance to occur. These are: 1) There are no known mineral values (KMV) or 2) Where the mineral reservation interferes with or precludes appropriate non-mineral surface development and that non-mineral development is a more beneficial use of the land than the mineral development. Remember that allegation, hypothesis or speculation that the conditions could or may exist in the future will not be a sufficient basis for conveyance. Convincing factual evidence for an applicant’s case for mineral conveyance must be made in order to achieve that conveyance. See 43 CFR 2720 0-1 to 0-3, and 0-6. CONCEPT OF KNOWN MINERAL VALUES Known mineral values means mineral rights in lands containing geologic formations that are valuable in the monetary sense for exploring, developing, or producing natural mineral deposits. The presence of such mineral deposits with potential for mineral development may be known because of previous exploration, or may be inferred based on geologic information (43-CFR 2720.0-5(b).

Jan 1, 2007

By David Cronan

"Most of the recent renewed interest in manganese nodule mining has been focused in the Clarion-Clipperton Zone (CCZ) in the NE tropical Pacific where nodules are rich in Mn, Ni and Cu. However, equally interesting, but compositionally different, nodules occur in the tropical central South Pacific (CSP). The CC Zone deposits lie in the International Seabed Area whereas those in the South Pacific lie mainly in the Exclusive Economic Zones of Island States, principally the Cook Islands and Kiribati. The CSP nodules should not be regarded as an alternative resource to CCZ nodules, as they are enriched in different elements. Rather, the CCZ nodules should be thought of as a source of one group of metals (Mn, Ni and Cu) and the CSP nodules the source of another group (see below), mutually complementing each other and to be mined in parallel for their different metals.Manganese nodule mining in the South Pacific has been mooted since the 1970s. However, new data on manganese nodule composition and abundance there have recently appeared. Also, a recently developed interest in 'rare', 'green' and 'technology' elements has necessitated a re-examination of old South Pacific nodule data for information on these elements (previously thought to be economically unimportant), and the re-analysis of the deposits to obtain new data on them. Additionally, current and possibly future applications to the UN to extend island 'continental shelf' areas necessitates an appraisal of the manganese nodules in these areas. These developments have prompted recent work that has helped to refine our understanding of the distribution and abundance of metals of traditional interest in South Pacific nodules, namely Mn, Co, Ni and Cu, but has also drawn attention to other elements of possible economic interest including titanium (Ti), vanadium (V) and the rare earth elements (REE)."

Sep 1, 2014

By W. O. Kerr

As in other industries, companies engaged in mining and extraction use and develop intellectual property (?IP?) in the form of new technologies or production processes. The development of IP assets in mining may occur as a byproduct of ongoing operations, or result from investment in dedicated R&D efforts. New technology may lower costs, increase quality of output, and/or increase operational efficiency or safety. Key business questions with respect to any new technology are how best to use IP assets, how to protect them and how to derive value from them. IP assets can provide a competitive advantage to a developing firm that uses the technology to improve its operating results. The developing firm can preclude others from using the technology if it believes that is the best way to exploit the technology?s value. Or, it can be shared with others taking care to ensure rights are maintained, thereby generating royalty income or strategic value through cross licensing or other business relationships. Either way, in order to fully realize the maximum economic benefit, innovators must protect the IP assets and control their dissemination.

Jan 1, 2012

By J. Wiebmer

Some thoroughbred racehorses are great routers (distance runners), others are sprinters. Some racehorses perform best on turf, others on dirt, and some in mud. To be a winner, you have to choose the right horse for the course. It's no different when looking at an electric cable shovel, a hydraulic shovel/excavator, or a wheel loader. Each loading tool has its own zone of application. To be a winner, you have to choose the right horse for your course.

Jan 1, 1993

By W. Choi

The present study revealed that the bioleachability of a chalcopyrite flotation concentrate is influenced by the semiconductor properties of CuFeS2. The overall reaction of biooxidation,

Jan 1, 1991

By Northcutt Ely

My topic today is our Nation's interest in the minerals beneath the oceans. I will state what I think should be our objectives, the means available to attain these objectives, and the obstacles to their accomplishment. It is possible that as early as this year of 1969 our country must make policy decisions on this subject, and that these, once made, will be almost irreversible. Two factors are hastening an. early decision. First, the 1958 Convention on the Continental Shelf becomes eligible for amendment after June 10, 1969, if the Assembly of the United Nations so decides. Second, the United Nations has created a permanent committee of 42 nations, which was preceded by an ad hoc committee of 35 nations, to study the question of the peaceful uses of the seabed "beyond the limits of national jurisdiction. While these measures purport to deal with the creation of a regime to govern mineral development on the deep sea floor beyond the limits of the jurisdiction of the coastal nations, it has become clear that the urgent issue is the extent to which this future regime shall acquire jurisdiction over the mineral resources of the continental margin, and receive royalties therefrom. This brings the proposal into potential collision with the interests of the coastal nations under the 1958 Convention on the Continental Shelf, including, of course, the United States.

Jan 1, 1969

By M. S. Davis

The Tek Process can produce masonry products such as bricks, roof or wall tiles, and block from virtually any inorganic waste. In the process the aggregate raw materials, portland cement, water and common chemicals are first mixed together; then mechanically subjected to several thousand pound pressure per square inch. This causes a novel chemical reaction between the cement, chemicals and water; producing the "patented" Tek adhesive binder which holds the aggregate together in a stone-like mix. Simultaneously, the desired product shape is formed. The building modules can have strengths of 8000 p.s.i. (pounds per square inch) with completely sound aggregates utilizing air curing for a period of 28 days. With most aggregates, 3000 p.s.i. is achieved within 24 hours. Eventual strengths usually exceed 5000 p.s.i. with almost any raw material. Water absorption ranges from 5-7.5 percent. Both absorption and strength figures are superior to the most rigid of any and all A.S.T.M. specifications for the highest quality bricks. In most locations, the product (when brick shaped is called Tekbrik) can be produced significantly more economically than can comparable grades of clay or other bricks, be- cause almost any inorganic waste materials or pollutant can be used as a raw material. The process results in a lower manufacturing cost as compared to clay bricks; fuel cost to operate a clay kiln represents a substantial portion of the total cost. Capital expenditure for a Tek plant also is lower due to the large investment in clay kilns. Transportation savings also are important, clay brick factories must be very large because the kilns are uneconomical unless they are large. Most bricks are manufactured at the sites of clay deposits in relatively uninhabited areas. The cost of transportation to the job site represents a considerable percentage of the selling price.

Jan 1, 1974

By Kenneth R. Krivanek

In recent years the widespread problems of air and water pollution generated by both population and industrial expansion have become a major public concern. Therefore, many municipalities are striving to achieve more efficient wastewater treatment processes so these wastewater's can be reintroduced into the waterways of our nation with little or no detrimental effects on the future beneficial use of that water. With this, improved treatment comes an ever increasing volume of wastewater sludge which must be disposed of in a manner of minimal impact on the environment. Furthermore, with demand for energy continually accelerating in this nation, our concern over high oil prices and our increasing dependency on foreign oil sources, there has been an ever growing interest in the largest energy source that are nation has, coal. However, surface mining of coal can cause many environmental problems when adequate precautions are not faithfully adhered to. These problems include water pollution from silt and/or clay erosion and acid runoff, produced by oxidation and hydrolysis of pyrite; i.e., FeS2 + 3/02 + H20 + FeSO4 + H2SO4. One method of wastewater sludge disposal which can utilize large volumes of sludge for a beneficial project that may not compound our environmental problems is spray irrigation, to either depleted farmland or to abandoned strip-mined soils. Sludge is characteristically high in organics, as well as having near neutral to alkaline pH properties. With these two qualities it possesses a potential for neutralizing acid strip mine spoils, which would enhance the establishment of a vegetative ground cover. Sludge can accomplish this by lowering the oxidation potential, reducing the solubility of iron and aluminum and by the chelation of metals, thereby

Jan 1, 1977

THE QUARTETTE Mine near Searchlight, NV, a mine that first operated in the 1890s, could begin processing ore again by September. Jetco Enterprises Inc. plans to work through the tailings and ore close to the surface followed by plans for an openpit mine. It is one of at least three new mining efforts in the region, the Associated Press reported. Another is north of Searchlight, with yet another across the Colorado River in Arizona, east of Bullhead City. Gold mining is rare in southern Nevada. The area generally lacks the rock type that contains gold deposits. Restrictions on federal wilderness areas and protections for the desert tortoise also play a role. Gold veins in the region are generally small and erratic in length and height, Bill Durbin, a geologist and chief of southern Nevada operations for the Nevada Division of Minerals told the Associated Press. L.R. Tad Tinnell, president of Jetco Enterprises, has long eyed the mine. From 1993 to 1995, he explored and drilled on the property, which was still owned by Searchlight Mercantile.

Sep 1, 2013