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By Russell C. Drew

The United States has long been recognized for its ability to marshall the many tools of its scientists and engineers to meet national threats or crises. Two major World Wars, the Dust Bowl, the Soviet Missile threat, Sputnik, and more recently the Energy Crisis have stimulated military weapons development, massive land reclamation and water management programs, NASA, and the Space Program, Project Independence, and soon a new agency, the Energy Research and Development Administration. While our record of successful responses to these major national concerns lends support to the expectation that we will succeed in dealing with the current energy problem and potential future crises as well, the crisis mode of response is becoming increasingly wasteful of funds and human and natural resources. This waste, while always of a concern, is a more important factor than previously because of the accelerating pace at which the world has been shrinking, relatively, in comparison to its human population and that population's increasing demand for resources, both renewable and nonrenewable. If present growth patterns continue, in the year 2000 there will be two people to feed, clothe, house, and satisfy for every one person that existed in 1970. On a finite planet, with finite land areas, limited resources, and only partial understanding of the means by which future problems can be addressed, one of the major threats to mankind will be scarcity and one of our major challenges will be better management of our resources. The challenge will be to guide Federal investments in R&D that are of sufficient magnitude and in the proper

Jan 1, 1974

By G. L. Dollinger, W. H. Hamilton

INTRODUCTION Design and development of new products generally proceeds through a phase of initial development and discovery based on the evolution of existing arts, followed by technical innovation and development based on both pure and applied research. The development of the mechanical tunnel boring machine (TBM) has followed a similar pattern, with the first machines closely resembling continuous coal miners. In general, however, the design of TBM's to date has been more a result of evolution and discovery than of new technical innovation, even though large sums of money have been spent on research and development. In particular, the results of experimental laboratory and field investigations have had little effect on tunnel boring machine design, and the better performance of TBM's today over those of 10 or 15 years ago, is due more to increased mechanical reliability and greater operating experience, than to improvements in penetration rates and rock fracture capability. The improvements made, have been mainly by the machine and cutter manufacturers who recognize the greater efficiency and economic advantage of utilizing large single row cutters with high load capacity along with large edge spacing. Are there any improvements to be made, therefore, in TBM performance without new and dramatic technological breakthroughs? Can TBM manufacturers design greater performance into their machines by a logical extension of the present art, and by applying what has been learned in the laboratory and field? Some, for example, believe that the kerf cutting system of boring rock is at, or close to, its opti¬mum and little improvement can be made in the present TBM concept.

Jan 1, 1979

By N. ?peh

The purpose of the paper is to present a way of assessing nonrenewable lignite resources by means of sustainability indicators. An introductory presentation of the origin and characteristics of the discussed nonrenewable natural resources is followed by the study and analysis of separate sustainability indicators. Out of many, only the ones that would directly relate to the explored coal deposit were studied. Some different viewpoints such as economic, social and environmental were assessed inside the studied landscape structure and in relation to other provincial resources using the indicators that are closely linked with the explored lignite reserves. Exploitation of coal as an underground nonrenewable natural resource, has been taking place in the ?alek valley for more than 120 years. However, about 60% of the coal will still be left underground since not all coal will have been extracted when the mine closes. According to the regional and wider national strategic goals concerning the use of natural resources and electricity production in the future, the sustainable aspect of the exploitation of the geologically well explored reserves is emphasized in the paper. Finally, we have tried to evaluate the role and the meaning of the studied underground natural resources for further sustainable development of the ?alek valley and placed stress on the most questionable spheres that should be considered preferentially.

Jan 1, 2007

A new fluid bed lime calcining plant is converting high quality limestone into quicklime at the Cape Lime facility in Vredendal, South Africa. The plant was supplied by Metso Minerals. Cape Lime, established in 1946, operates two limestone and dolomite mines in South Africa. The high quality Vredendal limestone deposits are suitable for the production of lime for water treatment and for manufacturing precipitated calcium carbonate.

Jan 1, 2003

By Edgar E. Vidal, Patrick R. Taylor

Standard textbook equations for heterogeneous kinetics typically utilize a constant driving force to solve for rates and times of reactions. In order to more closely model real systems, equations and solutions are presented for particle leaching kinetics in which the driving force is decreased as the reactions proceeds. In addition, models for continuous co-current and continuous counter current aqueous-solid reactions are presented.

Jan 1, 2005

By P. Zhang

The results of bench-scale testing of five flotation processes for the separation of dolomite from phosphate are discussed. Each process is compared in terms of phosphate recovery, MgO content of the concentrate and reagent consumption. Water quality was found to play a major role in the performance of these processes. The effect of water hardness, in addition to other parameters, are discussed.

Jan 1, 1997

By E. K. Albert

In 1977, Congress enacted Title IV of the Surface Mining Control and Reclamation Act (SMCRA), providing for an "abandoned ml.ne reclamation fund". This fund, taken from a fee collected from operating coal mines, provides capital for the reclamation process. However, given the number and extent of abandoned mine sites in some states, the question of project selection is important. This paper describes a project in progress to create a Management Information System application for project ranking under multiple objectives. The benefit of this project for the need of new environmental control technologies will be discussed.

Jan 1, 1990

By G. Tapia, R. J. Kelley

Empresa Minera de Mantos Blancos S.A. operates two copper mines in Chile: Mantos Blancos and Mantoverde. Oxide ore is processed by acid leaching followed by SX-EW to produce copper cathodes. In order to define the leach process adequately for each ore, an extensive metallurgical testwork program was carried out during the feasibility study for each of these projects. A combination of heap and dump leaching was selected for Mantoverde, while a modification to the existing vat leach operation was selected for Mantos Blancos.

Jan 1, 1998

By N. Lydakis ? Simantiris

Preliminary results of a mineralogical, geo-chemical and nutrient analysis of soil samples collected from Omalos polje-plateau are presented. This study is part of a project concerning the relationship of lithology and mineralogy characteristics of soils of different geological origin from the island of Crete with their chemical composition, and more specifically with their ionic nutrients content. The results presented in this work show a relatively good correlation of the mineralogy and the bulk content of the soils examined with the available nutrients in soil solution.

Jan 1, 2005

By Zhe Wang, Tichang Sun, Yongqiang Zhao, Zhengyao Li

Coal-based reduction followed by magnetic separation is a promising technology for processing refractory iron ores. Analysis of the size distribution of metallic iron particles is an effective approach for exploring the mechanisms of coal-based reduction. As metallic iron particles exhibit very complex shapes compared with nature ores, approaches for measuring and characterising metallic iron particles still remain unclear. In this study, the size of metallic iron particles was measured and characterised using manual point-counting by optical microscopy technics and image analysis. The effects of CaF2 as an additive on behaviour of the particle size distribution (i.e. mean size and cumulative frequency distribution) were also determined. Results indicate that CaF2 had a significant effect on the growth of metallic iron particles. When the CaF2 dosage increased from 0 to 8%, the mean size according to the area method increased from 9.03 to 16.28 μm, while the promotion effect gradually weakened and generated many fine metallic iron particles when the CaF2 dosage exceeded 8%. An increase in CaF2 dosage also led to cumulative distribution curves gradually shifting to the right mainly because F− can break the crystal structure of each phase during the carbothermic reduction of titanomagnetite and reduce the stability of the lattice structure, thus reducing the melting point and accelerating the growth of metallic iron grains. Compared to different measuring methods, the area method is a more suitable approach for measuring and characterising the size of metallic iron particles.

Sep 18, 2020

By W. F. Mullen

Within the scope of this discussion, artificial dimension stone is defined as any manufactured product used as a substitute for natural dimension stone. The history of the development of these substitute materials is reviewed briefly, representative characteristics of each product are listed, several analyses of their market position are presented, and suggestions are made for recapturing markets lost to these products and preventing additional inroads.

Jan 1, 1959

By D. W. Fuerstenau, S. Raghavan

This paper presents a brief summary of some of the thermodynamic aspects of flotation processes. Thermodynamic considerations that control interfacial and wetting behavior in mineral/water/air systems are discussed. Particular attention is given to the thermodynamics of collector adsorption.

Jan 1, 1976

By Wallace W. Roepke, Richard C. Olson

To adequately attack the longwall dust problem, the US Bureau of Mines funded a contract to define dust sources on a longwall mine face area. The study examined the shearer during sumping, cutting, and tramming, the conveyor, and the roof supports. Tests showed the shearer to be the major dust source. Introduction Long-term illnesses place a heavy burden on miners, the mining industry, and taxpayers. Black lung payments to more than 400,000 miners and their survivors exceeded $9 billion between 1970 and 1980. They are continuing at a rate of $1 billion per year. Recent MSHA data indicate more than 50% of the longwall faces are still out of compliance with the 2 mg/m3 (0.00007 oz per cu ft) respirable dust regulation. Allowable dust limits are often further reduced owing to the presence of silica dust. This substantially increases the problem's severity. Research in the 1970s showed that by modifying the mining method through changing drum-type mining machines from high rpm shallow cutting to slow rpm deep cutting, both specific dust and energy could be reduced (Black et al., 1978; Ludlow and Wilson, 1982; Roepke, Lindroth, and Myren, 1976). The coal mining industry is using more longwall equipment to economically obtain high productivity. This high production rate, however, makes it difficult for longwalls to meet the legal dust standard. Research is showing how both these concerns may be addressed at the mining face. Results reported here explain the relationship of various major elements of the longwall system to dust generation on the longwall face. This paper is based on work completed by Foster-Miller Associates Inc. Objectives were to differentiate dust sources on the longwall face and to quantify dust levels for various elements of the shearer drum. The work was accomplished in two phases. Jonathon Ludlow, project engineer for FMA, developed and performed the necessary testing (Ludlow and Marshall, 1983). Bradley, Hadden, and Weston (1983) have done evaluations on British coal mines that produced similar results to those reported here. They found causative rela¬tionships between haulage speed, production, depth cut, drum speed, and dust generation. They also found that roof support movement increased the dustiness, whereas this work indicated that support movement had only a minor effect on total dust exposure. Both of these results are valid when the variation of mining conditions is analyzed. British mines are deeper than US mines. Therefore, roof rocks and coal are more fragmented than in the shallower US mines. Other reasons for the dust differences include the weaker shales found in Britain and the variation of roof support equipment designs between the UK and the US. Four mines in this report had rock roofs and, thus, would be less dusty. The fifth longwall mine had a coal roof, but the large cross-sectional area and high air velocity minimized dust exposure. Mines and Equipment Five underground longwall mine sites were tested (Fig. 1). All were using double-ended ranging-drum shearers (derds) with some variations in equipment. The mines and equipment details are shown in Table 1. No modification of mining equipment or operating cycles was made during the first phase of testing. The mining process observed followed the normal mine operating procedures. Three GCA RAM-1 respirable dust monitors and two vortex anemometers with cycle notations on portable tape recorders were used in each face area. The start and end of each cycle segment were recorded. Dust monitors record the dust levels once every 10 seconds, thus providing a relatively continuous real time indication of change in

Jan 8, 1984

By Ernest Baafi, David Drew

Microsoft Excel based ultimate pit limit (UPL) optimiser has been developed to determine the greatest economic value of an orebody. UPL manipulates a given geological block model to define an ultimate pit limit using either the moving cone, method or Korobov algorithm or Lerchs-Grossman technique. UPL is designed to be an adjunct to MS Excel; the cells in Excel are excellent analogue to the blocks in a geological model, providing X-Y dimensions in an easily viewable and editable state. The use of individual worksheets within an Excel workbook provides the necessary depth to a 3-D block model.

Jan 1, 2002

By Andrew I. Hustrulid

The discrete element method has successfully been used to model the behavior of material flow in transfer stations. With position, velocity, and applied forces for every particle and boundary in the simulation available at increments of 10-5 seconds, the next critical step is the presentation of this data in a concise and beneficial form. This paper discusses several methods of presenting the data from discrete element simulations that are used to improve the performance of a transfer station. These measurements are also used as a learning tool to better understand and visualize how material transfers from one belt to the next.

Jan 1, 1998

By H. M. Breza

Utilization of Bucket Wheel Excavators and Overland Conveyor Systems to remove overburden provides increased productivity and flexibility to a surface mining operation. The utilization of such a system at the Texasgulf Inc. Aurora, North Carolina Mine has significantly improved the overall productivity of the mining operation. System flexibility is evidenced by adaptation to operation requirements such as mining area moves, movement of excavated overburden to designated sites, selective handling of overburden, spoil placement contouring, and providing an environmentally sound and safe operation. System productivity is evidenced by actual case studies relating to overall production, excavation rates, and cost effectiveness.

Jan 1, 1993

By Spencer R. Titley

Nearly three decades of intense research, corresponding with a period of unparalleled discovery and the advent of scientific advances and hypotheses of ore formation, has resulted in a great body process-focused research concerning how ore deposits form. The development of process models and their application has proceeded more or less in step. Discoveries have been made in mineralized regions such as provinces and districts but generally without a comparably developed understanding of why provinces and ore bodies exist and, except in general terms, where ore deposits are within districts and regions. The process of discovery is still referred to as search and exploration budgets are heavily weighted toward exploration drilling.

Jan 1, 1995

By R. K. Singhal

The underground coal mining systems have kept pace with the developments that have occurred in other types of mining industry. A diversified group of machines with high horsepower motors, built-in microprocessor technology and with numerous options to satisfy the miners need in a varying geological environment are now available. A brief review of this existing technology and its likely status within the next 21 years is presented. Discussed also are some of the on-going advanced developments in electronic mechanization, remote control and automation together with mine wide data monitoring and management systems and facilities to process and transmit data to remote computerized stations.

Jan 1, 1989

By Christopher J. Bise

INTRODUCTION Face haulage in underground mines and pit haulage in surface mines are the principal domains of rubber- tired haulage vehicles. In underground mines, cable- reeled or battery-operated shuttle cars and diesel-powered load-haul-dump vehicles are used; trucks are primarily used in surface mines. Although many concerns go into the selection of rubber-tired haulage vehicles, such as clearance and tire life, the most important factor from a mine-planning standpoint is the production capability of the vehicle in the mine environment. Therefore, this chapter will address this topic. UNDERGROUND FACE-HAULAGE VEHICLES The selection process for underground face-haulage vehicles is, in some respects, much simpler than that of the other haulage systems discussed to this point. It is simpler because these vehicles, which transfer the mined material from the face to the intermediate haul¬age system, are manufactured in various size ranges to cope with the confinement of underground opening widths and heights. However, since these vehicles oper¬ated in an intermittent fashion in conjunction with a constantly advancing face, the system's lack of perma¬nence and overall dynamic nature create a more diffi¬cult situation for predicting productivity. The emphasis in this section will be on prediction of productivity. There are three fundamental steps that must be taken to analyze the productivity potential of any face¬haulage system: l) Recognize the geologic (seam thickness, etc. ) and mining (opening widths, etc.) constraints that affect the velocity/clearance aspects of the haulage equipment, and select equipment from manufacturers' specifications with these con¬straints in mind. 2) Secure the elemental times of the face-haulage system. 3) Incorporate the elemental times into an accepta¬ble mine plan. By recognizing the geologic and mining constraints that affect the system layout, parameters, such as vehi¬cle payload, tonnage to be hauled per cut, and haulage distances, can easily be determined. Elemental times can be developed in two ways: 1) In an existing operation, a time study of the dynamic system can be conducted by placing three time-study engineers at the following static locations; (1) near the loading machine, (2) near the change-out point outby the face, and (3) near the dump. By synchronizing their watches and recording the actions of the haulage vehicles at these three locations, their time studies can be reduced to provide elemental times, such as vehicle tram rates (empty or loaded), vehicle discharge times, and loading rates. 2) In the absence of an existing operation, average values for the elemental times can be provided from other mines operating in similar condi¬tions, or by the manufacturers themselves.

Jan 1, 1986

By W. G. Pariseau, S. C. Schmelter

The destabilizing effect of water pressure on rock-mass stability is examined quantitatively by the finite element method. A coupled code that accounts for the simultaneous effects of rock-mass deformation and transient fluid flow is used for this purpose. The traditional soil-mechanics assumption of an incompressible fluid is shown to be untenable for the analysis of porous, fractured rock slopes. A Mandel-Cryer effect, whish is a transitory but elevated and potentially destabilizing water pressure following a cut, was not observed.

Jan 1, 1999