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By S. Miller, A. Krasner, M. Sizintsev, S. Schafrik, H. -P. Chiu, J. Sottile, A. Rajvanshi, Z. Agioutantis

In recent years, a great deal of effort has been put into automating mining equipment with the goal of improving worker health and safety and increasing mine productivity. Significant progress has been made in automating mining equipment such as load-haul-dumps and drills in underground environments where global positioning systems are unavailable. This paper addresses automating the task of positioning the shuttle-car (SC) under the continuous-miner (CM) coaldischarge conveyor during cutting and loading operations. A stereo depth camera is mounted on the SC. Machine learning based algorithms are applied on the camera’s output to identify the CM discharge conveyor and segment the scene into various regions such as roof, ribs, and personnel. This information is used to plan the shuttle car path to the CM discharge conveyor. The approach currently uses a 1/6th scale continuous miner and shuttle car in an appropriately scaled mock mine

Mar 2, 2022

By C. C. White

Although many notable scientific investigations relating to roof control have been made, roof control still must be considered one of the more baffling problems confronting the miner. Each year contributions are made to our understanding and techniques in dealing with various single phases of the overall problem, however, an equation considering all the variables involved in roof control, if formulated, would indeed be hopelessly complex. Among the factors to be considered is first, gravity which is always acting but which is sometimes less of a problem than lateral forces. There are lateral forces due to expansion, resulting from the weight of overlying rock; to these must be added lateral stresses of orogenic or tectonic orgin, which may be enormous. Stresses due to plastic flow of beds, water pressure, gas pressure, expansion due to absorption of water, faults, joints, fractures, pot heads, and the like may complicate the solution. Therefore, we must base decisions on roof control, and roof bolting in particular, largely on experience, and far too often on few "knowns" and many "unknowns", The development of "in situ" roof trusses may prove of benefit because, they unlike roof bolting, promise positive calculable roof support. These trusses require installation of steel tensioned rods in the roof, which rods are arranged to produce a stress pattern similar to a bridge truss, the roof rock acting to transmit the compression forces. The simplest form of truss (see figure 1) consists merely of two steel rods anchored at the back of holes drilled at an angle of approximately 45° over the pillars, collared near the the middle of the room, the lower ends of the rods being connected together by tierods and turnbuckles. Used in this way, a 3/4" diameter rod can offer greater support than a 10" x 5-3/4" wide flange steel beam. By tightening the turnbuckle, uplist on the roof can be produced,, the downward reaction being transmitted to the pillars by the rods. This simplest form of truss has been used in rooms up to 24' in width. Trusses of four panels, that is, consisting of a truss within a truss, as shown in figure 2, have been used successfully in rooms 30' wide. (figs 2 & 3) It appears a 6 panel truss could be used in a 40, wide room.

Jan 1, 1968

By Louis A. Panek

Research on roof bolting has developed significant information with respect to the functions that can be performed by properly installed bolts and the methods that can be used to ensure that effective installation has been achieved. The present paper brings together results that are pertinent to the design of a bolting system for reinforcing horizontally stratified mine roof with vertical bolts. The design approach is based on the use of bolts to decrease the maximum bending stress within an arbitrary sequence of roof strata (such as shown by figure 1) in which the only loads are the weights of the individual beds. The use of rock bolts to achieve other objectives, such as to stabilize a fractured rock mass on the periphery of a mine opening (3), is excluded from consideration herein.

Jan 1, 1964

By Herbert S. Richey

Two hundred years ago next April, our forebears embarked upon the difficult path to national independence. They succeeded, and shook off the yoke of foreign domination. In the ensuing two centuries, the country was mobilized several times to protect that political and economic independence from foreign domination. These efforts were also successful. Thus, as we stand here on the threshold of our third century of political independence, we can thank previous generations and congratulate ourselves for establishing and maintaining the world's oldest republic. Now -- once again -- the United States faces the challenge of foreign intervention into our economy. This time the battleground is resource avail- ability. America has been blessed with enormous resources. Whether we speak of minerals or timber or water or "amber waves of grain," this nation has benefitted from a resource base that is the envy of the world. This asset, coupled with a political system that permitted us to develop it, has been the physical backbone of our independence. Without the economic independence that this resource base has given us, the political independence we fought for would have been tenuous, at best.

Jan 1, 1975

By L. G. Austin

A program has been written to combine the Klimpel-Austin approximate model for liberation in a binary system with a mill model applicable to ball milling. The model applies for a system where the volume fraction of valuable B in host matrix A is small. The mill model is treated as an equivalent series of fully-mixed reactors. Twenty-three classes of material are considered: pure A; pure B; unchanged AB; 0-10.2 B in AB either as surfac- exposed B or as wholly-contained grains of B; 10-20% B in AB, surface-exposed or wholly- contained;etc.. to 90-100% /b ub /ABm syrface-exposed or wholly-contained. Illustrative cases are given making reasonable assumptions concerning relative rates of breakage and primary breakage distribution functions for each class of material.

Jan 1, 1986

By C. J. Johnson

As the U.S. coal industry moves into the next century, it is becoming more apparent that the effective application of new technology is the only way it can remain competitive in the energy marketplace. Examples of this emphasis are with us today in such diverse areas as face-ventilation and excavation-equipment applications. The focus of this new technology is directed toward improvements in health and safety, cost control, and productivity. Room-and-pillar mining accounts for approximately 80% of the nation's underground coal production; this percentage is not expected to decrease markedly in the near future. As such, this paper analyzes the impacts of the changing technological climate on future room-and-pillar operations by comparing a base-case section (current) to three scenarios incorporating new or emerging technology. A microcomputer-based comparative analysis will reflect the changes in section production and costs.

Jan 1, 1988

By J. T. Hanks

Process development is one of the principal tasks required in the course of turning an exploration discovery into a mine. Exploration geologists should have an understanding of the more important metallurgical processes and the test work required for each process. The paper discusses the important metallurgical processes, the test work and sample requirements for each, and the costs and time requirements to accomplish the testing. The limitations of reverse circulation drill samples for metallurgical testing are discussed. The level of process definition required to support engineering studies: scoping, pre-feasibility and feasibility studies are also described.

Jan 1, 1997

By Frank S. Hicks, Y. Charles Guan, Glenn A. Gruber

This paper describes a two-part program funded by the Florida Institute of Phosphate Research and performed by Jacobs. The first part of the program was to examine the application of ultrasonic treatment to clean phosphate particle surfaces. Florida phosphate pebble and rougher flotation feeds were treated in an ultrasonic trough to remove clays. Also, the de-oiling of rougher concentrates by ultrasonic treatment was tested. In order to improve the clay removal efficiency, viscosities of primary cyclone overflow from six beneficiation plants were studied in the second part of the program. Viscosities for different samples at the same clay % solids vary significantly, and increase exponentially with clay % solids content for the same sample. A method of controlling cyclone operation using on-line viscosity measurements and pump box level sensors is proposed to logically improve primary cyclone performance.

Jan 1, 2002

By Alexander N. Winchell

"The wash ore area on the Mesabi iron range covers a regionof the iron bearing formation extending from Grand Rapids on the west to the Hibbing district, about forty miles eastward. Not all of the developed ore bodies are of wash structure; some are of such grades that they can be shipped direct as merchants able ore. It is safe to say, however, that 65 per cent of the ore is of a possible wash structure and of too high a silica content to be classified as merchantable ore. The increase in the number of washing plants completed each year on the western Mesabi shows that ,the product must be of a structure desirable for furnace operation. The following is a list of plants which were . in operation, under construction, or with plans completed, at the end of 1918:"

Jan 1, 1920

By T. J. Joiner

A critical demand exists to develop new mineral resources, and the need for exploration techniques to supplement costly test drilling is becoming; more acute. In the past few years more industries have begun experimenting with geophysical methods to locate and define mineral deposits and delineate reserves. The new techniques have proven profitable in many instances. As a part of a broad long range program to study the mineral resources of Alabama, and in response to requests from land owners and mining companies, the Geological Survey of Alabama is investi¬gating the occurrence of bauxite and kaolin deposits in the Eufeula area. This project is supported by special funds appropriated for this purpose by the Alabama Legislature.

Jan 1, 1966

By K. H. E. Kroemer

Selecting persons who are unlikely to suffer an overexertion injury is one of three methods to reduce the risk of musculo-skeletal disorders in manual material handling. This paper describes the underlying models, methods, and techniques for such personnel selection. In particular, it describes the isoinertial LIFTEST in which persons actually lift weights to assess their capability for doing so on the job.

Jan 1, 1985

By M. B. Freeman

Acrylic polymers have been found to be effective dispersants and stabilizers in a wide variety of mineral processing applications including rheology control in concentrated slurries. This paper will describe these low molecular weight, water-soluble polymeric dispersants and provide a basis for how they function in concentrated slurries based on computer molecular modeling and applications results. Data on homopolymers as well as copolymers of acrylic acid will be presented to demonstrate the optimization of a polymeric dispersant in preparing high solids slurries of inorganic materials such as kaolin, calcium carbonate, lime, and magnesium hydroxide.

Jan 1, 1996

By BO HYUN KIM, MARK K. LARSON

The floor-heave and no-floor-heave phenomena at a western U.S. coal mine could not be properly simulated in numerical models using conventional shear-dominant failure criteria. Although the previous numerical study using FLAC3D very reasonably demonstrated these phenomena, 3DEC modeling in conjunction with the discrete fracture network (DFN) technique was performed to better understand the true behavior of floor heave associated with underground mining in an anisotropic stress field. As a result, the latter models predicted floor heave that agreed with relative amounts of observed heave from each gateroad system, but the cause of heave was mainly related to the degree of anisotropy instead of the size of the pillar.

Sep 1, 2022

By James R. Arnold, John O. Marsden

Introduction Metallurgical accounting practices have been revolutionized over the past 15 years by the introduction of low cost personal computers and easy- to-use spreadsheet software. The Chimney Creek metallurgical accounting system takes full advantage of these advances. Data is provided by a PLC-based process control system, IBM data logging, operator logsheets and assay results from an automatatic plant sampling system. The data is organized and stored in an IBM PS/2 system using Lotus 123 and customized accounting programs to provide a comprehensive information management system. Metallurgical accounting for gold plants should ideally provide information for the following: a) Gold production accounting b) Day-to-day process control and operation c) Metallurgical evaluation and process optimization The Chimney Creek system provides all of these while overcoming specific accounting problems presented by SAG milling a coarse feed, grinding in cyanide and dump leaching run-of-mine material. Process description Gold Fields' Chimney Creek mine is located 47 miles northeast of Winnemucca, Nevada, at the northern end of the Osgood Mountains. Ore is processed by a combination of dump leaching and milling processes. The dump leach operation treats approximately 2.0 million tons per year of low grade ore (0.030 oz/ton). Run-of-mine ore is top dumped in 40 foot high pads. The use of three solution ponds for leaching enables an intermediate solution to be recirculated to the leach pad to reduce the pregnant solution flowrate and increase gold tenor of solution to the carbon-in-column (CIC) recovery circuit. Gold recovery is approximately 65% by this method. The milling process employs a SAG mill-ball mill grinding circuit to treat 900,000 tons per year at an average grade of 0.19 oz/ton. The ore is crushed to minus 12" in a jaw crusher prior to feeding the SAG mill. Cyanide is added to the grinding circuit to start gold dissolution as early as possible. After grinding, leaching of the ore is continued in a unique two-stage counter current decantation circuit 1 with 12 hours of leaching between stages . 85% of the soluble gold is recovered from the first stage thickener overflow in carbon columns (CIC). The second stage underflow is treated in a scavenger carbon-in-pulp (CIP) plant. Ultimate gold recovery is over 95%. Loaded carbon from both the dump leaching and milling processes is pressure stripped by hot cyanide solution and gold is recovered from the resulting solution by zinc precipitation. The precipitate is retorted for mercury removal and smelted into bullion. The plant flowsheet appears in Figure 1. Data collection Data for daily metallurgical accounting is obtained from three sources: a) Plant sampling b) Process control system c) Operator logsheets All of the data collection for metallurgical accounting is based around the 12-hour shift operating schedule. Sampling All critical sampling for gold production accounting is performed by automatic samplers (Figure 2). Heath & Sherwood two-stage sampling systems are used for sampling all slurry streams (cyclone overflow, CIP feed and CIP tails). The automatic sampler consists of a pneumatically operated primary sample cutter and a continuous rotary secondary splitter. The cyclone overflow and CIP tails are the most critical samples since these are used to calculate gold into and out of the plant on a shiftly basis. The CIP feed sample gives additional information concerning intermediate dissolution and recovery

Jan 1, 1990

By Wenming Wang, Edgar E. Vidal, Scott A. Shuey, Patrick R. Taylor, Judith C. Gomez

Introduction In modern society, vanadium is defined as a strategic metal. Some 90% of the global consumption is used as an alloying agent for carbon steels, tool steels, and high-strength low-alloy steels (particularly for pipelines). Advanced titanium-aluminum-vanadium alloys are seeing application in the aerospace industry. Small but ever growing amounts are finding application as catalysts or in electronics. New uses are continually being discovered for this metal. One example of a new application is the vanadium-redox battery for use in generation plants and back-up power sources. Vanadium is found in a large number of minerals, of which the most important are carnotite, roscoelite, vanadinite, mottramite, and patronite. Just over a third of the world's vanadium is produced as a primary product; the balance is a by-product of the iron and steel, oil refining, power generation and uranium enrichment industries. Vanadium can also be sourced by recycling spent catalysts from the petrochemical industry and ash produced by the combustion of oil emulsion in power stations. However, recycling activities are believed to account for only a small amount of total world supply. Vanadium is recovered from these ores largely as the pentoxide (V2O5) [1]. The major sources of vanadium-bearing magnetite ores are scattered throughout Australia, China, Russia, and South Africa. Current estimates of world’s Proven & Probable vanadium reserves are of the order of 41.3 million tones [2, 3]. Commercial vanadium-bearing titaniferous magnetite deposits can be found in Kachkanar, Russia; Pan Zhihua, China; Bushveld, South Africa; and Windimurra, Western Australia [4]. Other deposits have been found in New Zealand, Canada, and India, among other countries. Vanadium consumption in the steel sector has increased some 7% per ton of steel over the last 10 years as new alloying applications have been found to improve steel's strength-to-weight ratio. Future demand from the aerospace and nuclear industries for non-ferrous vanadium alloys such as titanium and super-alloys is also likely to grow. Vanadium is usually added in the form of ferrovanadium, a vanadium-iron alloy. Vanadium compounds, especially the pentoxide form, are used in the ceramics, glass, and dye industries, and are also important as catalysts in the chemical industry. While established approaches may be used at an industrial scale to treat vanadium-bearing titaniferous magnetite ores in several countries, new alternatives are being developed worldwide. This review will give short overview of the treatment of vanadium-bearing titaniferous magnetite ores, an overview of direct reduction and direct smelting processes and an approach to determine technical alternatives for the property.

Jan 1, 2005

By G. Jim Cardwell

The question "what constituents should be determined?" is one that defies a simple answer, because earth scientist being what you are, the rock and mineral analyst will eventually be called upon to determine about three quarters of the elements in the periodic table. The concentrations of these analyses will range from as low as 1 ppb to 100% of the material being analyzed. The most important thing to remember about a quantitative analytical result is that it can only be an estimate of the concentration of the analyte present. A measure of the reliability of that estimate is given by statistically derived statements of the precision and accuracy of the measurement. When evaluating your data an understanding of precision and accuracy are of paramount importance. Precision is the measure of agreement between replicate values while the accuracy of a determination is the concordance between it and the true value. There is no quarantee, however, that a precise answer is an accurate one. The numerical difference between the two values is the error. When evaluating your data, the repeats analyzed with your samples will identify the precision and control standards of U.S.G.S. or Canadian Certified Materials quality will identify the accuracy. The main problem is this data is routinely withheld from the report, or was it ever included in the analysis of your samples?

Jan 1, 1983

By J. Leonard Frame

A coal-fired fluidized bed combustion (FBC) system will be installed at the Owatonna Tool Company, Owatonna, Minnesota. Two FBC combustors will burn solid fuels: coal, petroleum coke, and wood and paper wastes. Crushed dolomitic limestone will be used to control sulfur emissions to EPA limits. The combustors will supply indirectly heated hot air and hot water for paint drying operations, washing processes, and space heating. The program is sponsored by the United States Department of Energy and the Owatonna Tool Company, and is one of five programs designed to demonstrate industrial applications of coal-fired fluidized bed equipment. The paper will describe the combustion system and the results of development tests with dolomitic limestone for sulfur emission control.

Jan 1, 1978

By R. J. Pindred

Discussion by R.J. Pindred In his paper, Davis presents an overview of risk. He also introduces the Capital Asset Processing Model (CAPM) as a foundation for selecting the appropriate discount rate for a mining project. While applying portfolio theory is more defensible than the ad hoc adjustment of discount rates, the CAPM is not a panacea. CAPM shortcomings [The CAPM, as Davis stated, is expressed in the equation: ri=rf+pi4) where ri is the project discount rate rf is the risk free interest rate (3i is the project beta, and 0 is the market risk premium (rm - rf)] Application of the CAPM is more difficult than Davis indicates. Valuation is prospective, while the CAPM parameters are historical. Beta is determined from a regression analysis of historical data, while the beta needed for valuation is the expected beta. Betas are known to be unstable and the regressions that generate them often have low explanatory power. The difficulty of estimating a "project" beta must also be considered. Thus, the beta that is used in the CAPM will be based on the analyst's judgment. Like Cavender's discount rate, this judgment can lead to different project NPVs. Subjectivity in valuation cannot be avoided by a mechanical application of the CAPM. The risk-free rate, which Davis identifies as a short-term real rate of 4%, is also subject to scrutiny. A mining project is not a short-term investment and no single risk-free rate is appropriate for all of the cash flows. The hypothetical mine discussed in Cavender's paper is a six-year project. One might argue for the application of a risk-free rate from the Treasury yield curve at the duration of the project (in a bond-duration sense). This, too, is inappropriate. The risk-free rate should be matched to the timing of the cash flow. These rates can be determined by calculating the implied forward rates from the yield curve using a procedure known as "bootstrapping." It is likely that each of the project's cash flows would be discounted at a different rate. Commodity prices Davis criticizes the "ad hoc adjustment to the discount rate." Yet, in his discussion of the value of stochastic simulation, he suggests that the gold price be modeled as a "random walk, with or without a trend." This is essentially an arbitrary modeling of price risk. Consider that a liquid market in gold futures exists. The futures' price curve, which is closely related to the market's estimate of future spot gold prices, should be used to provide inputs to the model. This is especially true of a relatively short six-year project. Alternatively, as Davis correctly points out, a risk-averse investor can sell the commodity short to hedge price risk. Is it any more correct, in the portfolio sense, to account for price risk at all ?? References Cavender, B., 1992, "Determination of the optimum lifetime of a mining project using discounted cash flow and option pricing techniques," Mining Engineering, Vol. 44, No. 10, pp.1262-1268 Fabozzi, F.J., 1993, Bond Markets, Analysis and Strategies, Second Edition, Prentice Hall, Inc. Higgins, R.C., 1992, Analysis for Financial Management, Third Edition, Richard D. Irwin, Inc. Solnik, B., 1991, International Investments, Second Edition, Addison Wesley Reply by G.A. Davis Pindred discusses two issues related to my paper, the shortcomings of the Capital Asset Pricing Model (CAPM) and which commodity price values to use in the valuation exercise. Even though these topics are not directly related to the use or misuse of Monte Carlo simulation, they are important points to take into consideration in valuation exercises. Since I do not appear to have addressed these issues satisfactorily in my original paper, I will comment on each here. Pindred agrees with me that applying portfolio theory, and specifically the CAPM, to the selection of project discount rates is more defensible than ad hoc methods. But he then points out that the application of the CAPM to project valuation is more difficult that I indicate. It is true that the CAPM is a difficult tool for project valuation in general,. But the application of the CAPM to mining projects is one of the easiest I can think of. The biggest problem with using the CAPM for project valuation is coming up with an expected project beta. I suggest a project beta for gold projects of 0.45. The "true" value might be 0.35, 0.55 or whatever. Pindred correctly notes that the selection of the appropriate project beta is based

Jan 1, 1996

By David Humphreys

Assumptions about future commodity prices need to be made with close regard to the purposes for which they are being used. Prices generated for financial planning or trading purposes are unlikely to be suitable for the longer run purposes of project evaluation and reserve estimation. In this latter context, price assumptions need to be realistic, stable and rooted in a rigorous fundamental analysis of long run industry drivers. Amongst the factors to be considered in such analysis are price history, production costs and structural dynamics. It is also important that prices adopted are consistent with other information being used by a company in its decision-making.

Jan 1, 2003

By P. Marcheselli, Jean-Yves Peron

A twin tube tunnel of 2 000 meters long and an internal diameter of 6.90 m has been excavated through alluvial ground, with low overburden, using a 8.0 m diameter Earth Pressure Balanced tunneling machine with foam injection and extruded concrete behind segment.

Jan 1, 1995