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By David Akers, Clifford Raleigh, Glenn Shirey

Under a Cooperative Agreement with the U.S. Department of Energy’s National Energy Technology Laboratory (NETL) and the Mining Industry of the Future Program, CQ Inc. is demonstrating the GranuFlow™ process for improving the recovery of fine-sized coal in commercial coal preparation facilities. The State of Pennsylvania’s Energy Harvest Grant Program is also providing funding for this project. The GranuFlow technology involves the addition of an asphalt emulsion to a slurry of fine-sized coal (<100 mesh or 0.15 mm, typically froth flotation concentrate) before mechanical dewatering in screen-bowl centrifuges. The emulsion selectively agglomerates the carbon-rich particles, resulting in increased particle size and improved recovery of the coal fines during the dewatering process. This paper summarizes the test conditions and current results for both bench-scale investigations and full-scale commercial plant demonstrations.

Jan 1, 2005

By W. Kuckshinrichs

Metallic raw material flows are characterized by a complex global network of producers and consumers, as well as by a multitude of ecological, economic and social impacts across national boundaries and on different scales. This leads to the need to develop methodologies, which allow identifying obstacles that prevent metallic raw material flows to contribute to sustainable development. From a scientific point of view CRC 525 (Martens 2003) has developed an holistic indicator set consisting of approximately 80 different indicators. This set is taking into account the multi-dimensional character of sustainable development. Moreover the indicators reflect different system boundaries according to different actor levels and decision contexts. The full indicator set is important in scientific considerations and suitable for scientific awareness creation. However, to fulfil the function of a decision support approach for political and economic decision-makers some modifications are of central concern. At first a reduction of the full indicator set by selection of core indicators enables decision-makers to deal with complex issues of contrary economic and societal protection targets. Secondly, as thresholds of indicators justify societal call for action, they are discussed against its political or scientific origin. The proposed methodology is exemplified by indicator-based studies of the material flow of aluminium.

Jan 1, 2003

By L. C. Atkinson, E. A. Azrag, T. M. Hanna

The results of using a simple analytical solution and a relatively complex numerical model to estimate ground water inflow to an open pit mine are compared. The analytical solution assumes lateral, radial flow to a fully penetrating pit in an idealized confined aquifer, whereas the numerical model simulates fully three-dimensional flow to a partially penetrating pit from a water table aquifer. The latter is a more realistic simulation of the problem, but the former method is significantly easier to use. Comparison of the results obtained with the two methods for some typical hydrogeologic conditions encountered in mining yields ratios between them in the range of 0.2 to 0.6. These values can be used as a coefficient in the Pit Flow analytical solution to produce reasonable estimates of in-flow even when there are significant differences from the idealized conditions implicit in its application.

Jan 1, 1995

By E. B. McNew, J. M. Barnes, A. E. Torma

The applicability of biosorbent materials for the removal of uranium and other heavy metals from synthetic and actual uranium mil 1 tailing (UMT) solutions has been investigated. The biosorbent materials used in this study were barium loaded beads of alginate, alginate-dextran sulfate, alginate-carrageenan, and alginate-xanthan gum. These studies were performed in stirred vessels and packed columns. It was observed that 100 percent of the uranium could be removed from a synthetic solution following 2 hours of contact time in a stirred vessel, and 80-100% of U, V, Mo, Mn, Sr, and Zn could be removed from a UMT effluent solution with a packed column. Kinetic evaluations were performed, using a generalized rate equation, on the biosorption of uranium with these barium loaded beads.

Jan 1, 1992

By William Wraith

The availability of computer resources and data management technology, together with the prudent use of scientific management concepts, has made it possible to achieve important improvements in the control of maintenance and materials activities in the mining and minerals processing organization. The introduction of minicomputers and. the greatly improved efficiency of computer systems in general have put the use of computer technology within the reach of even the smaller mining companies which probably could not have afforded them just five to ten years ago. A number of progressive companies have implemented computer-based maintenance, purchasing, and supply inventory control systems. Using modern safety stock, demand forecasting, parts reliability analysis, and other control concepts, these new systems have helped minimize production losses by reducing the frequency and severity of supply shortages and unplanned repairs. At the same time, these systems are helping to conserve scarce capital resources by better utilization of supply inventory investments, reduced expenditures for maintenance, less frequent equipment replacements due to improved maintenance reliability, and greater capacity utilization of existing facilities.

Jan 1, 1979

By C. Tompouloglou

The innovation in a technological field is reflected by the Research and Development (R & D) activity in it. It is explained why patent literature is a more reliable indicator than non-patent literature for the assessment of the R & D activity in the technological fields considered. Consequently the R & D activity is measured in this article through the patent applications filed in the fields considered. The pattern of patent application filings in Drilling, Mining, Tunneling and accessory technologies is analyzed at an international scale over the period 1990-2000. A statistical analysis of the fluctuation of the number of patent applications per year, per country and per technological field is performed. The technological fields are defined on the basis of the internal patent classification used in the European Patent Office. The article attempts to detect the high activity and ?cutting edge? technologies over said period, to relate them to political or financial events and possibly to foresee the ?cutting edge? technologies of the future in which potential investors could be successful. Strong patents are revealed on the basis of the frequency of their citations by the applicants in patent applications or by the patent examiners in the search report. International as well as specific national trends in the innovation are spotted and analyzed.

Jan 1, 2003

By Yoshihiro Kawarabata

INTRODUCTION The shield-driven method in Japan has been adopted widely in soft ground tunneling, namely, subway, water supply, sewer and utility tunnels, and recently this is an indispensable method in urban area. Since this method was started to adopt on a full scale from the beginning of 1960, construction achievements in length were about 830 km for 15 years until 1974 (1). According to the recent informations of the Japan Tunneling Association, the achievement in length under construction as of December, 1977, was about 350 km (2) and the extention of increase in shield-driven method can be guessed (Tab. 1). Tab. 1 - Achievement in Length by Shield-driven Method (As of December, 1977, Unit: m) (---): Achievement by Okumura Corporation [ ]

Jan 1, 1979

By L. M. English

A basic model was developed to help assess methane control needs for the longwall mining of coal in gassy areas. Rather than depending on reservoir and rock mechanical theories, it uses an empirically determined gas emission rate as an input, and it operates on the assumption that, within a specific region and zone, gas emissions will be relatively equivalent for uniform incremental volumes of gob created by mining. The computer program divides longwall panels into segments, keeps track of the face advance and generates emission rates and volumes for both the entire panel and for individual zones within the panel by summing values for all undermined segments. This model can aid in the determina¬tion of the number, size and location of vertical wells or other methane-control applications that are needed for gob gas control.

Jan 1, 2000

By J. C. Yingling, R. Kumar, J. Sottile

The capability for on-line measurement of the quality characteristics of conveyed coal now enables mine operators to take advantage of the inherent heterogeneity of those streams and split them into wash and no-wash stocks. Relative to processing the entire stream, this reduces the amount of coal that must be washed at the mine and, thereby reducing processing costs, recovery losses and refuse-genera¬tion levels. In this paper, new ap¬proaches for optimal control of the segregation process using time-se¬ries models and empirical distribu¬tions are presented and demon¬strated using field data.

Jan 1, 2000

By W. M. Shaver, W. R. Dengler

INTRODUCTION In Canada, most of the rock being broken in underground metal mines is being carried out using traditional drilling and blasting methods. Despite advances being made in hard rock boring and other, more exotic techniques, it is Dynatec&apos;s belief that the traditional methods will continue to prevail for many years to come. It is also our belief that modest research efforts expended on the traditional methods will result in substantial financial benefits to the mining and rock tunnelling businesses. Dynatec has pursued productivity improvements through the use of long rounds in both shaft sinking and lateral development. The concept of longer rounds was developed by Dynatec on the Craig Shaft Sinking Project (RETC 1991). This paper reviews the Craig Shaft Long Round success. This technology was subsequently utilized to sink the two shafts at Aur Resources with great success. The development of a Long Round Jumbo for tunnelling is a natural progression of the long round technology developed for the Craig Shaft. RECENT HISTORY OF SHAFT SINKING Shaft sinking is one of the oldest and most difficult mining methods. Due to the relatively small amount of shaft sinking in proportion to tunnelling and

Jan 1, 1993

By Gregg E. Korbin, Robin B. Dill, Corey T. Dare, Tor L. Brekke, Larry R. Myer

A study was conducted to develop a fundamental understanding of the relationship between the size of an advancing tunnel face, the rate of excavation, and stand-up time in squeezing ground. Stand-up time is defined as the time elapsed after excavation that an unsupported tunnel face will remain stable. Squeezing ground is argillaceous rock or soil that exhibits pronounced time dependence of deformation and strength properties in-situ. A case history study documented the nature, causes, and solutions of several cases of stand-up time problems observed in the field. Then, in the laboratory, a series of physical model tests were performed in which model tunnel size, face advance rate, material properties, and pressure (representing overburden pressure) were varied. Stand-up time was found to increase as advance rate was increased or tunnel size decreased. In addition, an influence of advance rate on the definition of stability ratios was established.

Jan 1, 1981

By Gurses Oner

In situ leaching is a relatively old mineral extraction method; however, historically only a small portion of copper has been produced from small scale operations. Recently, in situ leaching technology because of its intrinsic advantages over conventional mining and milling is being considered as a viable option for recovering copper from both low grade oxide and sulfide deposits. This paper presents the application of computers to investigate in situ technology using large whole core leaching experiments. Computers were applied to three different areas: (1) experimental control and data acquisition, (2) non-destructive evaluation of samples using x-ray computed tomography and image processing and (3) mathematical modelling and data analysis.

Jan 1, 1992

By E. Topuz, J. Mastoris

The problem of defining the optimum final limits of an open-pit mine has challenged the mining industry for the last three decades. The difficulty results mainly from the great number of variables involved and from the sheer computational effort required in real-life applications. An actual lignite deposit is used in this study to introduce and apply a new methodology that can be used as a basis for surface-mine design optimization. A geologic-reserves model of the deposit is first developed with the use of an integrated geostatistical-modeling package. The model is transformed into an economic one through the use of flexible objective function formulation(s). The final open-pit limits are then optimized using a competent commercial optimizer, and comparative-sensitivity analyses are performed to study the effect of some basic mining and economic parameters on the optimal pit design. The conclusions drawn can develop useful guidelines for decision making by the mine operator.

Jan 1, 1996

By Paul D. Tavares, John Forbes, Eric R. Drooff

As the existing major U.S. - Canada rail tunnel was too small to accommodate double-stack container cars, Canadian National Railways is constructing a new parallel tunnel with a 50% greater diameter. Starting in Sarnia, Ontario, the new shallow-cover bored tunnel runs under a large research building and several other structures in an oil refinery before travelling under the St. Clair River. Maximum predicted settlements to be caused by the 9.2 meter diameter earth pressure balance TBM in the soft St. Clair till were in excess of 100 millimeters. As such, these settlements had the potential to cause severe damage and disruption to the existing refinery. In order to reinforce the soft clays below the refinery research building and other structures, and to compensate for settlement caused by the tunnelling, the ground improvement method of Soil Fracture grouting was successfully applied for the first time in North America. This paper will describe the details of both the soil fracture grouting application and the elaborate electrolevel remote monitoring system used.

Jan 1, 1995

By Joaquin Marti, Peter A. Cundall

This paper reports on some recent work in which several schemes were developed to model jointed rock under high stress, with particular reference to the phenomenon of "block motion" observed during dynamic loading of underground structures. Three approaches were made, corresponding to an increasing relative importance of internal block deformations as compared to rigid block movements. The first one uses distinct element method and assumes internally rigid blocks, which can break, repeatedly, whenever an empirical crack criterion is met. In the second approach each block is allowed three degrees of freedom to deform internally. The third approach, still in the development stage, permits arbitrary deformation of all blocks, which are internally decomposed into finite-difference zones and automatically rezoned during slip to preserve the calculation accuracy on joints. The last two schemes allow arbitrary constitutive relations for the intact rock, and all three schemes permit the geometrical arrangement of joints to be arbitrarily complex, in contrast to normal Lagrange, finite-difference programs, which are unsuited to model discontinua.

Jan 1, 1979

By Leszek W. Lunarzewski, Adam L. Lunarzewski, Raymond C. Pilcher

The Floorgas and Roofgas simulation programs are used to identify strata relaxation zones and their boundaries, to assess active gas sources from coal seams and gas¬bearing rocks and to determine relevant gassiness prediction coefficients for any local longwall. The paper shows that by use of the print-outs from the Floorgas and Roofgas programs the following benefits are achievable: • identification of the shear and gas discharge zone positions in the floor, strata relaxation angles and various gas discharge zone positions in the roof, which are both relevant to local geological and mining conditions • optimisation of cross-measure drainage hole length, location, number and angle of inclination calculation and definition of gas make prediction coefficients such as the release ratio from adjacent coal seams, specific gas emission during longwall extraction and the relationships between gas make, longwall width and coal production levels.

Jan 1, 1995

By John Durkin, Steven Wirch, Fred N. Kissell, Steven Ruggieri

The Bureau of Mines has developed two expert systems to give advice on coal mine dust control, one for continuous miner sections, and another for longwalls. Prototype versions have been evaluated by coal operators and MSHA. Both systems query the user as to the nature and extent of the dust control problem. Typical questions asked deal with matters such as cutting sequence, current dust standards and characteristics of current dust control techniques. Advice given by the system generally does not focus on a single issue, but may suggest a variety of approaches consistent with the ability of the operator to practically implement what is suggested. Both were written using expert system development software called Insight 2+. The advantages of Insight 2+ for the user are: low cost, IBM-PC compatibility, and the fact that little prior experience with computers is required. For the developer, Insight offers an easy to use production rule language and goal driven structure as well as a wide variety of capabilities.

Jan 1, 1987

By R. L. Loofbourow, Robert R. Miller

Deep, stable, unlined space promises secure, efficient, acceptable solutions to several current problems. With truly favorable conditions, it can be economic as well. The basic requirement is sufficient sound, tight rock at required depth. This and unusual surface requirements point to special testing. An objective is to describe conditions for planners, estimators and contracts. A first stage concept study needn&apos;t be prolonged but should overlook nothing significant. Although observations and tests on core are considered essential, time and expense can be cut by supplementing then with tests on walls of rotary or percussion holes. In some places initial drilling could be shallow.

Jan 1, 1981

By George A. Hoffman, Richard J. Proctor

INTRODUCTION We will discuss here only the subway construction phase; that is, two to five years at a given location--not the long-term analysis. We also will compare some tunnel construction methods used for BART and in Los Angeles. Typically, urban planners and engineers try to balance a new mass transit system to include tunneled subways, cut-and-cover construction in city streets, and elevated guideways. Their decisions are based on many factors, most of which can be quantified. But there are some socio-economic-environmental factors which are almost intangible, or nonquantifiable, and these are rarely included in the final report for a rapid transit system. There are two reasons for this: First, it is difficult to evaluate disruptions and psychological inconveniences to individuals and to the community during the construction period, and even more difficult to assign costs because the valuations are always subjective. Second, the rapid transit project capital costs are given in the final report and the public knows them; but the intangible social costs are borne by the affected neighborhood community, not the entire city, and as such they are "hidden costs," which in fact may add as much as 25 percent to the total system cost.

Jan 1, 1974

By James W. Evans

It appears that all extractive processes involve, at one or more points, fluids (gases or liquids) and that the flow of the fluid is an essential part of the functioning of the process. Usually that flow is turbulent and the turbulent flow frequently determines the rates of mass and heat transfer as well as other important phenomena such as bubble/droplet breakup and coalescence, particle suspension, etc. Over the past decade many attempts have been made to model turbulent flows in metallurgical unit operations. The present paper summarizes some of that work. Amongst the operations considered are agitated leaching, ladle metallurgy, electrowinning/refin- ing, induction furnaces, Hall cells and electro- magnetic casting. Where possible, comparisons are made between model predictions and experimental results.

Jan 1, 1990