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By Tom C. Palanglo, Norbert Maerz

Control of crushing and grinding circuits ideally requires continuous particle size measurements on both in- and outgoing streams. Until recently, size distributions could only be obtained by screening methods, which were neither cost effective, frequent enough, nor timely. Input streams are often composed of large fragments, making screening prohibitive. Optical image processing systems, such as the WipFrag System, have been developed to the point that they are an extremely valuable tool to characterize, control, and fine-tune the comminution process. Although accuracy is less than that of screening, measurements are precise enough to detect relatively small changes in size distributions.

Jan 1, 2000

By F. L. Jackson

When using perlite as an insulation, it is important to determine the requirements for different applications as this influences the processing of the perlite. In cryogenic applications, perlite properties of low density and fine particle size are desirable, while Loose fill insulation applications require similar properties and water repellency. However, in perlite insulating concrete applications, a coarser particle, of higher density, is required to provide improved compression strength. The essential properties of perlite including, particle size, density and surface treatment are discussed in relation to the various insulation applications. Also typical mineral processing and manufacturing techniques are reviewed

Jan 1, 1983

By Stephen Hoffman

The Environmental Protection Agency (EPA) is investigating approaches to control non-coal mining wastes. In May 1988, the EPA's Office of Solid Waste (OSW) released a document that outlined an approach to manage non-coal mining wastes and materials. This document was called Strawman I. It was a staff-level approach designed to aid the continued participation of interested parties and to enhance EPA's understanding of mining waste issues. EPA has been working with states, public interest groups and the mining industry to gather information and to solicit input on waste management approaches. The involvement of the states in the Strawman process has been coordinated by the Mine Waste Task Force of the Western Governors' Association and the Interstate Mining Compact Commission. Involvement of public interest groups has been coordinated through Colorado Trout Unlimited. And the participation of the mining industry has been managed principally by the American Mining Congress. In May 1990, EPA released Strawman II. It was based on comments submitted to the EPA on Strawman I and on information given to the EPA by interested parties since 1988. Strawman II is again a staff-level approach to protect human health and the environment from wastes and other materials associated with non-coal mining. In September 1990, meetings were held with public interest groups and the mining industry to discuss their comments on Strawman II. By early 1991, the EPA expects to make a decision on how to proceed with program development.

Jan 1, 1990

By Prasannarao Dontula, Kal V. S. Sastry

Advances are made in the field of mineral processing on a continuing basis both in the industry and the academia. These advances do not always get used fully because of the inherent difficulties in the transfer of knowledge and reduction to practice. In recent years, knowledge engineering is being increasingly employed in other fields to overcome some of these difficulties. This paper presents a vision of how knowledge engineering can be applied to the benefit of the mineral processing industry and includes a discussion of associated principles, techniques, and advantages.

Jan 1, 1993

By H. C. Verakis

Permanent ventilation controls such as stoppings, overcasts, and undercasts for use in coal mines are required to meet MSHA’s safety standards for fire endurance and flexural strength. Due to technological advances in materials and their design for use as ventilation controls, an engineering program was established to evaluate newer or “nontraditional” ventilation controls. The program is intended to assist manufacturers, enforcement personnel and mine operators in determining if “nontraditional” ventilation controls, for example plastic membrane construction and lightweight block, meet the prescribed safety standards. The program is presented with a description of required tests and examples of products evaluated.

Jan 1, 2003

By Rilung Xu, Jerry C. Tien, Jian Liu

As underground mines become deeper and ventilation networs more complex, ventilation data becomes more complicated and voluminous, making timely ventilation planning and necessary changes more difficult. Oftentimes, ventilation engineers have to rely on special techques using graphs and schematic maps to carry out necessary ventilation planning [1, 4, 5, 6, 9, 10, 11, 12]. A different graphical method, similar to that reported by Taminago and Isobe [10], has been developed in China [13]. This method uses a two-dimensional diagram drawn from available ventilation survey results. It combines both the customary pressure-quantity diagram and ventilation schematic map, and can greatly expedite the interpretation of survey results, facilitate ventilation system design, short and long-range planning, and emergency planning.

Jan 1, 1993

By Thomas W. Camm

The U.S. Bureau of Mines has extensive experience estimating the cost of mining and mineral processing operations as an ongoing part of its information and analysis studies. With the increased interest in remediation of mine wastes, the USBM is developing a methodology to expand its cost estimating expertise to include costs of various remediation techniques applicable to mineral processing and mining wastes. By integrating waste remediation costs with existing USBM cost estimating systems for mine and mill operations, a comprehensive system for cost engineering studies will be developed.

Jan 1, 1995

By R. L. Garrett

The quality of mineral additives used in a drilling fluid (mud) can dramatically affect the fluid's properties and the overall cost of drilling an oil or gas well. The principally wed minerals are bentonite, barite, barite/hematite blends, and hematite alone. The high specific gravity minerals, barite and hematite, are used to increase drilling fluid density. Bentonite clay is used to increase drilling fluid viscosity and gel strength and to provide a low permeability filter cake. A multimillion dollar investment in a well and the safety of the personnel on the drilling rig can depend on how effectively these mud additives perform with other constituents in the mud. This paper points out effects caused by small amounts of certain carbonate and sulfide mineral impurities in barite or hematite and how polymeric extender additives in bentonites contribute to unpredictable behavior of a mud. Effects like these are the reason oil companies using these materials sometimes set their own quality standards beyond those already specified in APZ Spec. 13A. Also discussed in this paper are the current standardization activities of API Committee 13 on these minerals.

Jan 1, 1988

By Ahmet Unal

Inexpensive and effective means of delivering courses to mining engineers who live at remote and scattered locations remains to be a challenging issue. Computer-based instructorless but interactive multimedia delivery is a good substitute to traditional short courses and one-way broadcasts. Such a system, enhanced with a wide area network, is an inexpensive alternative to two-way broadcasts and even to a traditional university. Course material can either be delivered on compact disks (CDs) or on-line from the host servers over the phone lines using a personal computer and a modem. Although technically not feasible using ordinary telephone service lines at the present time without further modification, advances in this field indicate that this up and coming medium may dominate the competition in the future. This paper investigates the present and the future of this technology and discusses the experiences gained in creating and disseminating a prototype multimedia CD which was created at the Rock Mechanics and Explosives Research Institute of the University of Missouri-Rolla to teach a portion of a course in Ground Control. The hardware and software used in creating the audio, 3-0 graphics, animation dips, video clips, and movies are listed. The structure of the program and the way how interactivity was achieved is explained in detail.

Jan 1, 1996

By Stanley A. Bunk, Desmond J. Bruyns

The purpose of roasting gold ores is to release for extraction, typically by cyanidation, the small particles of gold which are surrounded by refractory stone. The roasting simply opens up passages for the penetration of solution into the interior of the ore particles. This is accomplished by the removal by volatilization or formation of volatile oxides of certain constituents such as sulfur, arsenic or antimony. Temperature is an important parameter. High temperatures tend to form a dense iron particle rather than a "spongy" calcine. The dense iron particles result in lower gold recoveries. High temperature can cause melting of some components which also results in gold encapsulation. Roasting of refractory gold ore concentrates has been practiced for decades. Multiple hearth, rotary kiln and muffle reactors were first used for roasting. Fluid bed roasting provided a low capital cost, low maintenance technology with better process control and soon became the favored technology. The first fluid bed concentrate roasters were commissioned in the late 1940's. Early fluid beds were "bubbling" type. Environmental considerations did not significantly impact on the design. Feedstocks were highly exothermic and reaction rates were relatively rapid. Roasting today must compete with other technologies for treatment of refractory ores. Ore bodies which are not

Jan 1, 1993

By A. Bruynesteyn

Most ores and coals contain sulphide minerals such as pyrite, FeS2, the sulphur portion of which is a ready substrate for a variety of sulphur oxidizing bacteria. Although there are several bacteria capable of oxidizing sulphide minerals, the most often discussed culprit is Thiobacillus ferrooxidans.. Oxygen from the air slowly oxidizes pyrite into sulphuric acid, but T- ferrooxidans can increase this reaction rate several 100,000 times.

Jan 1, 1991

By V. Srajer

Operations research includes the application of systems analysis to mining operations, the acquisition of field data and the creation and verification of computer models of these operations. These activities result in the generation of computerized mine planning tools which have a firm base-in observational facts. The Surface Mining Laboratory of the Canada Centre for Mineral and Energy Technology (CANMET), in Devon, Alberta has been engaged in operations research activities since 1982. The work includes computer simulation of truck/shovel, continuous mining equipment and dragline operations. Other examples include cooperative programs with industry (such as the demonstration and evaluation of an integrated truck management system), the development of a device to measure off-highway truck rolling resistance, and an automated remote data transmission network. The presentation outlines existing and proposed research projects of the Operations Research group.

Jan 1, 1989

By Werner Stahl, Karsten Keller

Vibration screens are commonly used not only in classifying bulk material but also in dewatering it. The lack of a comprehensive physical theory of dewatering often leads to difficulties in the design and operation of the vibration screens. Firstly, the dewatering of bulk material will be shown, based on a physical model. Because of the oscillatory motion of the liquid in the bulk, the inertial force of the accelerated liquid and the dripping of water out of the bulk or screen must be taken into special consideration. The physical model put forward shows the effect of the various operations parameters of dewatering screens. The comparison between dewatering theory and practice will be shown by measurements using coal, limestone, etc. Dewatering measurements, which have been conducted on a vibration screen, demonstrate that different vibration frequencies and rates of acceleration lead to different residual moistures. Finally, the possibilities of improving vibration dewatering will be described.

Jan 1, 1995

By James L. Whitlock, Amy E. James

During the past twenty years, numerous advances have been made in the technologies used to pretreat sulfidic refractory gold ores. These advances have included improved equipment design, increased gold recoveries, and reduced operating and capital costs. More recently, treatment of refractory gold ores has primarily been accomplished by pressure oxidation (POX), roasting, chlorine oxidation, or biooxidation. In addition to improving the time-proven processes of pressure oxidation and roasting, new and innovative approaches to biooxidation pretreatment of both concentrates and whole ores have been developed. Selecting the appropriate biooxidation technology depends on the nature of the refractoriness in the ore, economic gold recovery, plant design operating parameters (such as desired tonnage), site climatic conditions, and operating and capital costs, as well as several other deciding factors. The objective of this paper is to outline the biooxidation processes and technologies currently available for the recovery of gold from refractory sulfidic ores, to discuss the critical factors that affect plant design and operation, and to provide the metallurgist with a practical guide to choosing the appropriate biooxidation technology for a particular ore or concentrate.

Jan 1, 1999

By D. R. Baughman

Copper oxide deposits that may be considered for in situ leaching exist in unique geologic settings, different from uranium deposits. A large number of interrelated factors must be considered in wellfield design. Many of these factors are hard to quantify and are directly related to geologic features of the orebody. This paper discusses some of the important factors in wellfield design and suggests an outline for a design procedure.

Jan 1, 1988

By V. Srajer

Several optimization approaches used by the Canadian mining industry were used to investigate surface coal mining operations in Canada. A computer program was applied to optimize truck/shovel systems and for various analyses. The analyses of eight western Canadian coal mines included investigation of fleet imbalance, under- and over trucking, development of the criteria for automated truck control, comparison study of various haulers and loaders, haulage layout, driving conditions, machine performance, servicing and maintenance policies, etc. Each property investigated supplied background information for the study and cooperated in optimization studies. The truck/shovel system optimization study is demonstrated as a test case to outline procedures and step-by-step instruction for similar applications.

Jan 1, 1989

By H. T. Miller, L. M. Scott

Radiation exposures in Uranium operations may result from external beta-gamma radiation emitted by Uranium and its progeny, internal exposure to alpha and beta radiation due to the inhalation and ingestion of Uranium ores, Radon gas, and Radon progeny in mine, mill, and laboratory atmospheres and from the contamination of environmental working surfaces and clothing by Uranium-bearing compounds and ore. This paper summarizes occupational experience with reference to the exploration, surface mining, underground mining, milling and transport of Uranium by one company in the U.S. and Canada.

Jan 1, 1981

By Russell G. Slayback

An integral part of site investigations for shafts and underground workings should be hydrogeologic evaluations of the need for and method of ground-water control. Such investigations should include: 1. Classification of the problem by aquifer type. 2. Integration of other site investigations with hydrogeologic programs, including assessment of the need for water control. 3. Planning and conduct of aquifer tests tailored to the aquifer situation. 4. Evaluation of pumping requirements to achieve water control objectives. 5. Scheduling of dewatering for optimum results and costs. 6. Evaluation of environmental impacts of pumpage and water discharge. 7. Planning of operational monitoring for program modification and liability limitation. Early hydrogeologic involvement can result in avoiding unnecessary duplication in site investigations.

Jan 1, 1981

By V. Iordachita

In the beginning of the third millennium, the world mining industry has to cope with many challenges; the continuous need for mineral resource deposits and the mostly unsolved economic efforts should be accompanied with ecologic measures mankind has to take in order to avoid self-destruction. The present paper analyses the possibilities of using underground mining spaces in Romania for storing dangerous waste and suggests viable solutions. The characteristics of dangerous wastes and their disposal in suitable underground spaces are analyzed. Also, some methods for deactivating dangerous solid wastes as well as the importance of monitoring underground spaces in order to eliminate environmental impact risks are presented.

Jan 1, 2008

By Robert A. Hains, William P. Balaz, K. Payne

Ceramics are usually used to line chutes, pipes, dust collectors, separators, cyclones or bins where abrasive or corrosive material is moving. Improvements in ceramic manufacturing methods and quality, use of other abrasion resistant materials in combination with Alumina ceramic, improved adhesives and installation methods allow the use of Alumina ceramic tile in applications with impact. This paper discusses the criteria to determine if ceramics can provide a cost effective alternative to other liners for abrasive material handling applications, design parameters for liner systems, system costs, and case histories. The goal will be to provide a practical guide for improving the performance of existing ceramic lined systems or determining if ceramics is a cost effective solution for your abrasive material handling applications.

Jan 1, 1996