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By L. C. Galloway, G. L. Tiley

"Mine hoist brakes must meet the following statutory performance criteria:- There should be two independent braking systems; at least one should act directly on the hoist drum.-If one brake fail s, the others should be able to retard and stop the hoist safely before the descending conveyance, carrying the rated load, reaches any obstruction.- When all brakes apply, decelerations should not be so violent that men travelling in the conveyance are injured.- The brakes shall not overheat and fade during an emergency stop.This paper discusses design principles and capacities of caliper and disc type brakes, when applied to double drum and friction hoists of equivalent capacity.IntroductionThis paper is about the brakes that are used on mine hoists; their functions, especially in emergencies, typical design, and how they are operated, controlled, tested, and adjusted.There are two basic types of mine hoists:1. Drum hoists, where the ropes are attached to, and coil on drums. The simplest system has only one drum. Most such hoists, however, have two drums, attached to a common shaft. Ropes are wound on each drum in opposite directions, so that when one conveyance is being raised, the other is lowered. The conveynaces may travel in vertical or inclined shafts. In the latter case, the hoist s are referred to as slope hoists.2. Friction hoist s, where the headropes are not attached to the wheel, but are in contact with it for an angle of lap of, typically, between 180 and 195 degree s. Forces are transmitted from the hoist wheel to the head ropes by friction.The lower ends of the conveyances are connected to balance ropes , approximately the same weight per foot as the headropes."

Jan 1, 1986

By P. Somasundaran

Electrochemical properties of silicate minerals govern their behavior in processes such as flocculation and enhanced oil recovery that can occur at elevated temperatures. Knowledge of these properties as a function of temperature can be helpful in developing an under- standing of the role of these interfacial properties at non-ambient temperatures. Zeta potential of Sodium Kaolinite and quartz has been determined as a function of pH and temperature in this work. Both systems exhibited markedly different behavior at higher temperatures and also exhibited significant hysteresis. Results are examined in terms of possible dissolution of the minerals and surface reactions at different temperatures.

Jan 1, 1986

By J. W. Merks

At mineral processing plants the accuracy and precision characteristics of assays in mill feed, tailings and concentrate largely determine the reliability of the metallurgical balance. The accuracy of measurements is ensured by selecting effective sampling methods and efficient sample preparation procedures, and by effecting each phase without introducing a systematic error while the precision of measurements is determined by the sampling regime. Sampling systems and components, sampling methods and regimes, and sample preparation procedures will be reviewed. Different techniques to determine variance components for sampling, preparation and analysis, and to detect systematic errors in assays at mineral processing plants, will be discussed.

Jan 1, 1986

By Parrington PJ, Bailey A

Serious exploration for carbonate-hosted lead/zinc deposits in the Pillara district commenced in 1971 when Trend Exploration acquired exploration tenements covering stream sediment anomalies in the Limestone Billy Hills area. Shell Minerals managed the project from 1974 to 1976, and BHP Minerals Limited assumed management during 1976. Carbonate-hosted 'Mississippi-Valley- type' Pb-Zn deposits most commonly occur in Palaeozoic shallow marine carbonate complexes. At Pillara upper Devonian (Givetian/Frasnian) reef complexes are preserved on the flanks of Precambrian basement 'highs'. Within platform and atoll facies limestones sphalerite-galena- marcasite-calcite mineralisation occurs as disseminations, veins and breccia matrix, mostly associated with fractures and fault zones. Early exploration concentrated on detailed surface geochemistry and IP geophysical surveys, with geological mapping and shallow target percussion and diamond drilling. Results were discouraging and did not indicate potential for a shallow base metal resource. During 1976-77 BHP adopted a grid diamond drilling exploration technique and commenced testing an area of approximately 50 sq. km, initially using an 800 m square grid. In 1978 high grade mineralisation was intersected in an area subsequently named Blendevale. This was in the seventh diamond drill hole in the 800 m grid drilling programme, and to date more than 400 holes have been cored in the Pillara area. Detailed drilling at Blendevale has defined a number of mineralised breccia zones within an area of 2.4 km x 0.5 km, at depths of 100 m to 600 m below surface. The breccia bodies are associated with a series of north-south trending normal fault zones, forming a graben structure. The mineralisation occurs as breccia matrix surrounding unaltered limestone clasts, as veins filling steep fracture zones, and as

Jan 1, 1986

Improve safety at mineral operations that use cyanide leach solutions to recover precious metals from finely ground ores, Approach Provide an alternative, non-acidic means of cleaning processing systems such as the State-of-Maine filter system, thereby reducing the exposure of workers to toxic hydrogen cyanide gas (HCN), The Problem Many gold and silver mining operations use cyanide solutions to dissolve gold and silver from ores. The precious metals frequently are recovered from pregnant leach solutions by the Merrill-Crowe recovery process, whereby gold and silver is precipitated with zinc dust. When that method is used, suspended particles in the leach solution must be filtered out before zinc precipitation can occur. This filtering is accomplished with small packaged plants, such as the State-of-Maine (SOM) filtering system. Unfortunately, the filters become clogged with calcium carbonate scale after about 2 to 10 days of operation and must be cleaned before further precious metals recovery operations can continue, Cleaning the system is a hazardous task because the acid is not compatible with the alkaline cyanide leach solutions, and toxic hydrogen cyanide (HCN) gas may be produced when the acid and solution are mixed. That gas, if breathed or contacted with the skin, can cause cyanosis which may induce nausea and even asphyxia and death. To reduce this danger, the Bureau of Mines has devised a safer method of cleaning clogged filters,

Jan 1, 1986

By M. J. Ferrante

Relative enthalpies of high-purity disodium hexatitanate (Na2Ti6013) were measured at the Bureau of Mines to provide new thermodynamic data needed to advance the technology of materials. Measurements from 298.15 to 1,478 K were made by drop calorimetry with a copper block. Tabulated values are listed for the standard relative enthalpy, heat capacity, en-tropy, and Gibbs energy function between 298.15 and 1,500 K. Enthalpy data are also given in equation form and are combined with thermodynamic data from the literature to derive values of standard enthalpies of formation, Gibbs energies of formation, and logarithms of the equilibrium constants of formation. Similar calculations were made for the reaction of Na20 with Ti02.

Jan 1, 1986

By Dale R. Ralston, Roy E. Williams, Gerry V. Winter, George L. Bloomsburg

INTRODUCTION The majority of ground water flow models have been developed for large computer systems. Most of these operate under a batch mode of operation, that is, the data are input with a deck of punched cards. The advent of micro- and minicomputers over the last few years opens the possibility of adapting many of these large flow programs to the smaller computers. In general, this adaptation will require more computer time to run the program, but in many cases if the small computer is in-house, the overall cost may be less than that required for a large computer. There are also a number of peripheral devices that can be used to make the data input much easier. As an example, the use of a digitizer with a finite element or finite difference mesh reduces the data input time considerably; the use of a graphics terminal for display of the mesh immediately after it is developed shows immediately whether there are errors in the location of node points. DEVELOPMENT OF AN INTERACTIVE SYSTEM The finite element program, UNSAT2, has been used over the past several years by the authors for several ground water flow problems (Bloomsburg, 1977; Bloomsburg and Wells, 1978; Zahl and Bloomsburg, 1980). In the past these programs have been run on an IBM 370/ 145 computer under the batch mode of operation. One difficulty that has been encountered has been in determining the length of time step that must be specified for operation of the program. The problem is that if the time steps are too large, the program becomes un- stable and operation ceases. If this happens in the middle of the problem, the only alternative is to reduce the length of time step and repeat the entire run. This problem has been alleviated in other pro- grams by using a subroutine that determines the time step automatically. If the solution becomes unstable, the time step is reduced automatically and that portion of the solution is repeated. With an interactive system this can be done by storing the output pressures and restarting the program with the new output pressures. Under the batch mode of operation, there is an option in UNSAT2 that allows restarting of the program from the last point of solution, but this must be specified when originally starting the program. The interactive computer system that we use currently consists of a PDP 1 1 /23 with hard disk drive, CRT terminal, plotter, graphics terminal, digitizer, and printer. The computer has 256 K bytes of core storage and the hard disk drive will accept a 5.2 M byte disk. To run a large program on a computer such as this, some overlaying must occur; that is, subroutines are stored on disk and put into core storage only when they are actually needed for running the program. UNSAT2 required very few changes to run on this computer but some changes were necessary to take advantage of the interactive capabilities of the system. One of these changes consists of the development of a program called DBUILD to build the data file for running the program. This program calls for each piece of data by prompt statement and gives instructions for using the digitizer. The data are then entered in completely unformated form. The node points must be entered in order and the coordinates are determined automatically by the digitizer. The pressure readings or initial conditions on each node point are entered through the terminal. All element information also is entered through the terminal. After DBUILD is run the mesh may be displayed immediately on the graphics scope whereupon any error in node point

Jan 1, 1986

By K. Hanumantha Rao, A. Nayak, . K. S. Narasimhan, S. N. Mahapatra

Selective flocculation studies carried out with iron ore tailings generated at Kudremukh iron ore plant indicate that a concentrate containing 63% iron can be obtained from the tailings containing 34% iron with around 60% recovery. This opens up the possibility of recovering most of the iron lost in the tailings generated at 2 kt/h (2200 stph) while processing 22 Mt (24 million st) ore per year. This would mean that the productivity could increase by around 50%. In these studies, it has been established that caustic degraded tapioca starch is a most effective agent for selective flocculation. While potato starch after caustic degradation can also be used, neither the parent starch nor the amylopectin compound is as effective.

Jan 1, 1986

By Edehran Lotfi, Terrence Stobbe

INTRODUCTION Mobile excavating and handling equipment are important 'tools of trade' in the mining and construction industries. The handling of this equipment must be mastered so that its limitations are learned and its harmonic use with other pieces of equipment is practiced. he sudden growth in mobile excavating and handling equipment type, size, complexity, and application started after the Second World War. This growth has not been accompanied by pertinent human factors research. Investigations into the proper and safe handling of such equipment with due regard for human and machine limitations are lacking. One such piece of equipment is the front-end loader (FEL), which during one cycle of operation excavates, loads, and hauls, (Lotfi and Adler, 1981). The diversity of action by FEL is archetypical among excavating and handling equipment. Front-end loaders are the most rapidly proliferating type of equipment in the industry. Also, front-end loaders are involved in the highest number of accidents involving mobile excavating and handling equipment. In the period 1970 to 1978, FEL's were involved in 27% of all mobile equipment accidents in surface mining (Adkins, 1980). Improving operational safety and efficiency will reduce the frequency of accidents. The performance of the operators can be evaluated and improved by the following steps: first, define the operating conditions and the operator workload intensity (Adler and Lotfi, 1983), second, monitor the operator to evaluate his task performance, and third, make recommendations based on the findings. The stressful nature of the equipment operating task is an acknowledged fact (Field, 1980). However, a systematic measurement of stress evaluation is lacking. In this paper, methods for measuring mental stress and fatigue, are defined, the mental load which caused the stress is outlined, and stress measurement methods are proposed. MENTAL STRESS Mental stress has been described as a "specific somatic response to damage or the threat of damage by several environmental agents"

Jan 1, 1986

By J. B. Sabey, V. R. Degner, D. MacGillivray

"Hydrodynamics principals are applied to the design of a natural air ingestion flotation machine for coarse solids applications. Preliminary laboratory test data and subsequent operating plant flotation kinetic performance evaluations are reviewed. INTRODUCTIONThe concentration of potash (sylvite, KCI) from halite and other salts using flotation is well understood and practice a with much success. Reagent schemes and plant circuitry for obtaining the desired product recovery and grade have been established with proven performance. These flotation circuits normally process the medium and finer size particles, less than 30 mesh (600 microns).However, often the potash market trends specifically demand a coarse product size. This emphasis, accompanied by the existing high losses of coarse (+30 mesh) potash in flotation circuits, creates the need for development of a flotation machines specifically designed for coarse potash beneficiation.This technical challenge was undertaken by the WEMCO Research and Development Group. The specific objectives of this flotation machine development program were ( l) to achieve an ""Ultra Coarse Flotation Machine"" capable of adequately suspending and transporting particles in the 4 - 30 mesh (4.75 - 0.6 mm) size range at solids concentrations of 30% or greater and (2) ascertain metallurgical performance of this machine.This paper covers the development (both theoretical and mechanical/ hydrodynamic), the field test program and results, a discussion of applicable flotation kinetics, and conclusions of this ""Coarse Potash Flotation Machine"" development project."

Jan 1, 1986

By P. B. Marchant

"Based on laboratory and pilot scale continuous biooxidation of complex sulphide concentrates, commercial processing design and scaleup considerations are discussed. Capital and operating cost estimates for commercial biohydrometallurgical operations are summarized and potential applications of biotechnology are discussed. Biooxidation as an oxidative pretreatment alternative to enhance precious metals extraction from refractory sulphide concentrates in stirred tank reactors has received considerable attention recently due mainly to advances in the practical applicability of the process. Biooxidation of sulphides is certainly not a new process, however, application and control in large scale hydrometallurgical operations to treat refractory sulphides remains conceptual and the limited data available is restricted to relatively small laboratory and pilot scale operations. It is the intent of this paper to indicate scaleup and plant scale process design considerations for commercial bioleach circuits, based on recent operating experiences with laboratory and pilot scale continuous bioleach systems. An indication of the expected range of applications will be presented parameters for optimization will be discussed."

Jan 1, 1986

By W. M. Pytel

A simplified two-dimensional model to analyze time-dependent load distribution and surface subsidence associated with longwall mining geometries is described. The model is based on the theory of beams resting on inelastic foundations and includes visco-elastic behavior of immediate floor strata, non-linear behavior of coal pillars, elastic behavior of face supports, and visco-elastic behavior of the overburden strata. The relative importance of the different variables affecting the performance of longwall mining geometries from ground control point of view is also analyzed. The model has been validated for field observations from one Illinois longwall mine.

Jan 1, 1986

By R. Y. Wan

Recent research efforts have shown have shown selective solvation extraction of a gold cyanide ion-pair complex from alkaline cyanide solution is possible with organic phosphorus esters. These alkyl phosphorus esters such as tributyl phosphate (TBP) and di-n-butyl n-butyl phosphonate (DBBP) can selectively load gold to rather high levels, even in excess of 30 gpl. However, traditional stripping techniques are not particularly effective. In this regard, gold recovery by direct electrolysis of the organic phase has been found to be an interesting possibility. Further, the rate of direct electrodeposition from the organic phase can be improved significantly by using an aqueous/organic mixture. Direct electrodeposition of sheet gold from loaded DBBP was successfully accomplished at a current density of 8x10 4 amp/cm2 and 55°C from such a two-phase mixture with the aqueous phase as the continuous phase. No appreciable degradation the DBBP was found after 5 cycles of extraction and, electrodeposition. Finally, the applicability of the process strategy for an industrial situation was demonstrated by the successful treatment of waste gold cyanide electroplating solutions.

Jan 1, 1986

While I contemplate the formidable catalogue of bodies and organisations participating in this Conference and the impressive array of qualifications chalked up after the names of the representatives I am indeed honoured to be invited to address you. When I consider the theme you have chosen for your conference I am also somewhat daunted: "The Twenty First Century - Mining for Mankind". It is indeed dramatic, challenging. But what, I ask myself, can a mere KCMG say to all you professional fellows and doctors and academicians? It is not for me to stray on to the more esoteric areas that you will be covering, thereby running the risk of teaching my grandmother how to suck manganese nodules. On the other hand it seems to me that you deserve more than the courtesies, not to say banalities, that are sometimes - sadly, and unjustly - regarded as the stock in trade of diplomats.

Jan 1, 1986

By Ronald Althouse

During the past five years under contract with the U. S. Bureau of Mines (BOM Contract J0308002). West Virginia University's Mining Extension Service (WVU-MES) has designed, developed) and delivered to the mining industry a comprehensive training program for Mine Rescue (MR) teams and a management planning tool for Mine Emergency Preparedness. The Mine Rescue team program is systematically built on a set of training objectives, backed up by content, allowing mine operators to conduct team training activities. These materials are user-ready, provide the MR principles and practices for both initial and advanced training, and supply teams with exercises geared to problem-solving activities. In addition to an instructor's program guide, the eight (8) modules that comprise the initial (20 hour) MR training are: an Introduction to Mine Rescue, an Introduction to Self-Contained Breathing Apparatus (SCBA), a set of modules covering each approved minimum 2-hour SCBA (i.e.) the Draeger BO 174-A. the McCaa) the Aerolox. & the Scott Rescue-Pak), and a manual on Auxiliary Apparatus as well as the Chemox Auxiliary SCBA. Advanced, annual refresher training (40 hour) is covered by seven (7) modules that spell-out the principles and practices needed to establish surface organization, to handle mine gases as well as mine ventilation, to conduct exploration, for fires, firefighting, and explosions, to rescue survivors and recover bodies, and to accomplish a mine recovery. Approved by MSHA in 1984 to meet requirements for 30 CFO. Part 49, these materials provide a basis for trainers' instruction, for comparison of team capabilities, for modifying programs resources, and services, and for program planning. The Mine Emergency Preparedness Program (MEPP) is used by management as a tool in the preparation of company personnel for handling a mine emergency operation. As a wholly new program. MEPP depends upon development of a Mine Emergency Organization and Emergency Operations Procedures. It also requires regular scheduling of drills) periodic mock emergencies, and evaluation of organizational responses and program performance beyond required training of mine rescue teams. MEPP materials are arranged into three sets of guides: 1) the Preparedness Program System Guides include an Executive Summary, a Program Director's Guide Mine Emergency Organization, and Emergency Operations Procedures; 2) the Emergency Organization (MEO) User's Guides cover the Rescue and Advisory Division, the Technical/Safeguarding Division, and the Surface Support Division; and 3) the Emergency Procedures (EOPS) User's Guides detail Containment Level Procedures, Notification Level Procedures. Mobilization Level Procedures, and Deployment Level Procedures.

Jan 1, 1986

By S. K. Palm

Volatility is a fact of life in the mining industry. Prices of and demand for mineral products are among the most volatile of those for any product. The volatility of these markets wreaks havoc on both corporate management and the personal lives of mining people. Yet, until recently, it has been difficult to assess the impact of volatility on business strategy. This paper discusses how mining firms can profit from market volatility through an operations strategy that stresses operating flexibility. The foundation for our strategy analysis is the observation that a mine is analogous to a stock option. Techniques based on those developed to value stock options have recently been extended to the field of mine valuation. The insights provided by option pricing are very valuable in the development of mine operating strategy.

Jan 1, 1986

By T. W. Lloyd

Accurately predicting coal seam discontinuities is an important part of modern underground coal mining. Conventional methods of coal exploration sometimes fail to identify rapid variations that may seriously impact mining and quality. Radio Imaging Method (RIM), a geophysical approach to mapping longwall panels, has been developed where electromagnetic signals are transmitted and received though the coal block. The amount of signal loss for a given distance, when compared to the coal seam characteristics, identifies anomalous areas. A comparison of RIM predictions with actual geologic conditions encountered during longwall mining demonstrates the accuracy and usefulness of the data.

Jan 1, 1986

The Australian Mineral Industry's growth in the last two decades is directly related to the skill and experience of its consultants in mining, metallurgy, geology, finance, management, marketing, and engineering. The role of mining consultants needs to be re-examined, so that the quality of the service they deliver will continue to be adequate for the 1990's. One means of this evaluation is by examining Case Studies in the strategies and difficulties of developing contract and entrepreneurial research.

Jan 1, 1986

By Wai Wu, C. Haycocks

The majority of Appalachian coal deposits lie in a multi-seam environment. Historically, the decision to extract a particular seam has been based on ease of access, ownership and economics rather than ground control considerations. As mining progresses and seams are being mined out, it is increasingly common to find working and abandoned mines in close vertical proximity to each other. Such contiguous operations can produce both positive and negative ground control situations in neighboring seams. These ground control problems, defined as interaction problems, are frequently reported, and their severity can range from minor roof problems that may require no additional support to complete loss of a large section of coal reserves (Stemple, 1955; Peng & Chandra, 1980; Haycocks & Karmis, 1983; Su et al, 1984). As a consequence, interaction problems are of growing concern to the Appalachian underground coal industry. Although interaction problems in multi-seam mining have been recognized for many years and many investigations have been conducted to study the problems, the ground control principles involved in their development are only partially understood. Previous research has identified four interaction mechanisms: pillar load transfer, innerburden shearing, arching effects and upper seam subsidence (Haycocks et al, 1982; Haycocks & Karmis, 1983). Pillar load transfer mechanisms and innerburden shearing have been successfuly used to explain interaction phenomena associated with undermining operations, while arching and subsidence have been used to assess problems during overmining. In addition, interaction-controlling factors such as cover, innerburden and seam thicknesses, extraction percentages on both seams, time delay between operations on two seams, and characteristics of innerburden rock have been identified and utilized in evaluation of interaction effects (Haycocks & Karmis, 1983; Webster et a1.,1984). As an example, Figure 1 shows the relation of innerburden layering and thickness to interaction on the lower seam. The combination of such theoretical work and the analysis of case study information has made it possible to determine, with a certain degree of confidence, the interaction damage in undermining conditions. The results of such an approach have been sufficiently successful and complete to be incorporated into a software package to assist field engineers in estimating potential interaction effects when undermining a previously mined upper seam (Grenoble et al, 1984; Grenoble & Haycocks, 1985; Grenoble et al, 1985). Although the conventional finite element and photoelastic modeling techniques have been

Jan 1, 1986

Provide coal mine shafts/slopes with an optimum coal mine shaft fire and smoke protection system composed of reasonably-priced, reliable hardware. Approach Accident and injury data indicate that a relatively low percentage (5%) of underground coal mine fires occur in shafts or slopes. Nevertheless, shaft or slope fires are extremely serious because they block critical escape routes for miners. That also can happen when combustion products resulting from fires in other mine areas contaminate shahs and slopes. Seeking the optimum configuration for a shaft/slope fire and smoke protection systems, the Bureau of Mines gathered data on the performance of existing fire detection devices and signal telemetry systems In several mines, and analyzed the generic protection needs of the U.S. underground coal mining industry. The optimum system developed by the Bureau provided an adequate number of detectors, a wide area of coverage, and an extensive data acquisition, analysis, display, and storage capability. This system. recommended for fabrication and in-mine testing, consisted of a microcomputer-controlled master panel located in the test mine's slope hoist room, and four remote units. Two of the remote units were placed on the surface atop upcast ventilation shafts, a third was situated underground near the slope bottom, and a fourth was installed at the slope top in intake air.

Jan 1, 1986