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By M. A. Cristovici

The use of surfactants as wetting agents to suppress sulfide ore dust has been investigated. Numerous surfactants were examined to determine their characteristics and to investigate their ability to improve the wetting of the sulfide ore dust. However, the surfactants selected as suitable dust suppressors proved to have a negative effect on the flotation of ore contaminated with such reagents. A method was developed to eliminate the detrimental influence of dust-suppressing surfactants. It consisted of surfactant adsorption on activated carbon and separation of loaded carbon prior to flotation. The technique is simple and requires minimal changes in the plant flowsheet.

Jan 1, 1992

By P. R. Khangaonkar, G. Bhaskar Raju

Three types of flotation columns were developed with a column dia of 8.0 cm and a length of 160 cm. The first type consists of an ordinary column fitted with a porous plate at the bottom. The second type consists of two electrodes at the bottom to obtain very fine and uniform bubbles generated electrolytically and the third is a combination of first and second types, i.e. to get both electrolytic bubbles and air from the compressor through porous plate. Three different ores were tested-gold tailings for recovery of scheelite, copper tailings (chalcopyrite) and oxide copper ore. In the case of scheelite and copper oxides, good results were obtained with the first type of column itself, whereas the third type column was found fairly effective in the recovery of chalcopyrite. The variables like the effect of reagent concentration, column height above the feed point, feed flow rate, current density, air flow rate, particle size etc. were examined.

Jan 1, 1988

By Jeong-Heum Kim, Jan M. Mutmansky

The primary purpose of the research summarized in this paper was to experimentally investigate the performance of numerous mine ventilation network iterative solution procedures under controlled conditions to determine which procedures were most favorable in terms of number of iterations and total computational speed. The solution methods investigated included: (1) the Newton-Raphson method, (2) the Hardy Cross method, (3) the linear theory method, and (4) the second-order approximation method. The first three of these methods have been widely used while the fourth was formulated by the authors to investigate its potential for ventilation network computation. In addition to the four solution procedures, three methods for selecting the branches in the meshes and three methods for ordering the meshes for computational purposes were also studied during the investigation. As a result of these various options, a total of 36 combinations of solution methods, mesh selection procedures, and mesh ordering schemes were studied. To investigate the performance characteristics of these combinations, an identical set of 180 randomly chosen ventilation networks was used in sets of 30 networks at six different levels of complexity. Here, the level of complexity is defined as a function of the size (number of branches) and the density (number of nodes compared with the number of branches) of the network. To eliminate variations in the solution times due to differences arising from the fans, a single fan with a fixed characteristic was utilized in all the experiments. This paper will deal only with the results for the four iterative methods used to achieve solutions to the mine ventilation networks. The minimum-resistance spanning tree method for mesh selection and random mesh ordering was used throughout the analysis. The conclusions will be based upon a detailed accounting of the efficiency of each method using the total time to achieve a solution to each problem and averaged over the total problem set. However, the number of iterations and the time to complete each iteration will be studied in order to better understand the solution procedures.

Jan 1, 1991

By Rodrigo Estay Huidobro, Andrés Martinoli, Claudia Pavez-Orrego

The effects of induced seismicity caused by mining activities are one of the main problems that the mining industry faces. Although it has been documented by countries with a great mining tradition (United States, Canada, Australia and Chile) for over a century, the problem has been intensified throughout the years due to the greater depths that mineral extraction reaches, where the stress levels and environmental conditions increase the possibility of a rockburst occurrence. Seismic events inside the mine cause important losses of human lives and infrastructure damage. To deal with this problem it is necessary to implement several kinds of safety protocols. For example, seismic indicators allow to identify, through the analysis of a set of seismic parameters -magnitude, energy, time, decay rate, among others-, periods of time when a seismic event of considerable magnitude is most likely to occur. The objective of this work is to use the frictional energy generated by a microearthquake inside the mine as a seismic indicator, linking it with the occurrence of large magnitude seismic events which are outer the background activity. Thus, we seek to determine the set of seismic parameters which allow the best performance of the frictional energy/heat indicator. In the present study, we considered magnitude, frictional energy, and time as seismic parameters to study the efficiency of the proposed indicator. The optimal set of parameters was determined using two different methodologies: accumulated thermal energy and alert bands. The Piece Skill Score and the Accuracy indexes were used to evaluate each set of parameters. Both approaches show a high rate of true positive and true negative hits. Furthermore, it was concluded that both methods show complementary results in terms of the detection of critical events (Mw > 3.0).

Apr 26, 2022

Acid mine drainage is still a common problem in the northern Appalachian high sulfur coal region despite mining and reclamation practices applied to control it. Mining companies must treat water with alkali to raise pH and precipitate metals in order to discharge the water into receiving streams. Common chemicals used to treat drainage are limestone, hydrated lime, soda ash briquettes, caustic soda, and ammonia. Each chemical has advantages or disadvantages under specific conditions. A simple spreadsheet program was developed to evaluate costs of treating acid mine drainage across several specified water quality parameters and time horizons. Caustic soda and soda ash were shown to be cost effective for treating low flows and low acidity over short time periods. However, as quantity of water increased, quality decreased, and time horizon increased, the ammonia and hydrated lime systems were found to be much cheaper than caustic soda.

Jan 1, 1991

By W. F. Hahnert, P. A. S. Ralston

In off-line training of a rule-based controller, the significant measure of successful training is the quality of control provided by the generated rule set. In an adaptive or on-line control environment, performance is also measured by the ability to accurately maintain a satisfactory rule set, but within constraints on speed and/or resource availability. Very small population genetic algorithms, or microGAs, have been proposed as a means of capitalizing on the hill climbing characteristics of faster local optimization techniques while requiring less memory and retaining much of the robustness of traditional, larger population genetic search. A traditional genetic algorithm and a similar microGA are developed and applied to two control problems. The performance of these algorithms is analyzed with respect to (1) the quality of the rules learned, (2) the rate at which learning occurs, and (3) the memory resources required during learning.

Jan 1, 1993

By Wei Wu

A computer-aided method for optimization of bench blast design in surface mines is presented. The design procedures basically consist of two steps. Firstly, a series of normalized, full- scale bench crater tests must be carried out in the field to find the optimum burden that produces the largest amount of acceptable fragments and other parameters that defines the effective fracture zone. Next, the locations and initiation sequence of blast-holes will be determined in such a way that each hole, at its time of firing, will be responsible for same amount of burden rock and will be in a position favorable to effective fracture of burden rock. A computer software "B.B." which can assist the second step of the design is fully introduced and its application is illustrated by an example.

Jan 1, 1992

By F. Djahanguiri

The US Bureau of Mines con¬ducted research on underground stope leaching of metalliferous ores. Leaching underground would minimize the environmental impact of ore processing on the surface and would maximize minable reserves. An important aspect of this process is the minimization of pregnant solution losses and groundwater contamination by leach solutions. Bulkhead design and construction are important issues for solution control and stope-leaching economics. A reinforced-concrete bulkhead was designed, constructed and tested for solution control in an underground mine near Idaho Springs, CO. This paper presents the bulkhead-design methodology and construction procedure.

Jan 1, 1997

By S. C. Brown, R. C. G. Oliveira

Surface wettability, or contact angle, dictates a number of multiphase ensemble interactions that influence particulate dispersability and adhesion behavior (e.g., filler compatibility] in addition to a number of other phenomena including biocompatibility and bulk powder segregation. The wettability of particulate surfaces significantly impacts nearly all process industries; however, the available techniques to access this quantity are either relative, or tedious-and are application or industry specific. In this study, key features of existing techniques have been combined to design an improved method to delineate particle wettability that is simple, versatile and capable of providing reproducible measurements in an industrial environment.

Jan 1, 2003

By Bart Hogeweg

The development of deep sea mineral deposits creates a new horizon for the mining industry. In a field where mining technology meets deep-water offshore engineering, new challenges are faced to come to the successful exploitation of these deposits. With the absence of proven technology for the mining of these minerals, a ?technological green field? is entered. IHC Merwede (IHC), a global market leader in the dredging and wet mining industry, is on the frontline of these developments. MTI Holland, IHC Merwede?s research and development company, has undertaken a number research efforts focused on the successful development of technology for the mining of deep sea minerals. This paper highlights a number of these efforts and illustrates IHC?s continued dedication for the research and development of technology to enable the commercial mining of deep sea minerals.

Jan 1, 2008

If a fire occurs outby an underground coal mine section, the immediate safe evacuation of miners from the working section should always take precedence. Unfortunately, in many cases, the dedicated escapeways (escape routes) for the evacuation of the miners become contaminated by the byproducts of fire from the adjacent entries. The purpose of this paper is to present the ventilation-control process that would keep the escapeway free from contaminants and, thus, available for travel. A few scenarios of mine fires in longwall development panels are analyzed and discussed. To perform these studies, a mine fire simulator (MFS) was used. This (MFS) provides a dynamic representation of the fire's progress (in real time) and gives a color-graphic visualization of the spread of oxygen, combustion products and temperature of the gases throughout the ventilation system. Also presented and discussed are ways in which the MFS can be used as a training and teaching tool for miners and, particularly, for ventilation and safety specialists.

Jan 1, 1997

By Robert Sutton, Milan Sjaus

Conveyor pulleys are an important and integral component of a conveyor. Conveyors work in sequence to make up conveyor systems. Each conveyor system is only as reliable as its crudest component. If the pulley fails, then the whole material handling system stops. So what is the effect of this downtime? What are the costs of repair? How much are we willing to pay to solve the problem? What should we spend to prevent an unscheduled shutdown? Do we use the technological improvements at our disposal or do we ignore them to satisfy immediate cost savings? This study will focus on the cost of pulleys relative to the total conveyor cost, the cost of downtime, the maintenance costs and the costs for resolution of the problem. Some philosophic and design concepts are injected for illustration and discussion.

Jan 1, 2000

By James R. Boulton

Fire detection using Carbon Monoxide sensors is based on the assumption that a rise in the level of Carbon Monoxide in the atmosphere over a fixed, predetermined ambient level is indicative of a fire. The method is simple, reliable, and effective in those mines where the only source of CO is from undesired combustion. Ambience for this purpose is defined as that level of the gas that is present on a day to day basis whose source is not a fire. In a diesel powered mine the level of CO can and does vary so widely from hour to hour and minute to minute that the selection of a predetermined, fixed level represents a compromise between sensitivity and reliability. The compromise is a best of both and worst of both situations and the computer system often resembles the little boy who cried wolf instead of a state of the art early fire monitoring and detection system. Cyprus Coal personnel have developed method of determining the ambient level of CO in the atmosphere on a real time basis and using that dynamic ambient level to determine whether or not a fire exists in the mine. The method has been given the name of Wave Trend Crossing.

Jan 1, 1991

By B. J. Arnold, F. F. Aplan

A model incorporating rate and residence time to describe the froth flotation process was used to provide data for the evaluation of various kinetic flotation models and to provide scale-up information from laboratory to industrial scale coal froth flotation. Rate constants were determined in laboratory and plant froth flotation tests and the residence time distribution was measured for a bank of four 21 ft 3 (0.6 m3 ) WEMCO cells treating Upper Freeport seam coal and a bank of four 300 ft 3 (8.5 m3 ) cells treating Lower Kittanning seam coal. It was found that a lag time for continuous flotation should be incorporated into scale up models and that a kinetic froth factor ratio of between about 2.0 and 2.8 should also be used to scale up data from laboratory to plant scale.

Jan 1, 1989

By E. Sehner, G. Van Weert

Metal chloride pyrohydrolysis is a fifty year old technology, operating satisfactory in many plants around the world, mainly on ferrous chloride, The capabilities and costs of its two equipment options (spray roaster and fluid bed pyrohydrolysis) are well known. Why is the technology not more widely used in mineral processing, beyond the production of MgO and upgraded TiO2slag? After briefly reviewing chloride vs. sulphate process characteristics and existing plant operations, this paper will discuss pyrohydrolysis options for the mine developer using the processing of ilmenite, siliceous zinc oxides and oxidic nickel / cobalt ores as examples.

Jan 1, 2003

By T. N. Moore, E. M. De Souza

Because jackleg rock drills are a potential source of hand vibration exposure, they can effectively produce Hand Arm Vibration (HAV) Syndrome in their operators. This will affect operator efficiency and mine productivity. As a result, a significant amount of work has focused on redesigning rock drill handles using new materials to minimize hand-transmitted vibration. In previous work developed by the authors (1991), a detailed study was undertaken to determine the effectiveness of using elastomer covered handles in place of the standard steel design. The results indicated that, for an elastomer-based handle design, the overall acceleration level experienced by the hand can be reduced by as much as a factor of three, relative to the steel handle. It was also shown that this reduction takes place predominantly in the frequency range above 500 Hz. This paper presents an investigation of the long-term effectiveness of an elastomer-cushioned handle under different conditions underground. In this study, sponsored by the Mining Industry Research Organization of Canada (MIROC), a number of cushioned handles were quantitatively and qualitatively tested in five operating mines. The vibration testing program has indicated that the cushioned handle can reduce overall vibration levels by as much as a factor of three. The qualitative assessment program of the cushioned handles by the drill operators has indicated some degree of preference for the cushioned handles over the steel handles, if certain design modifications are performed. This research program indicated that cushioned handles have the potential to become the dominant method with regard to vibration reduction and operator performance.

Jan 1, 1994

By Don Stainbrook

Over a period of many years a highly automated computerized system of ore control has been developed at the Newmont Gold Company, (NGC). It is the purpose of this paper to review the development of this system, describe the setting in which it functions and to mention some of the future developments and enhancements. Discussion of the evolution of the system in a historical perspective helps to understand its present status and illuminate some thinking about future directions of development.

Jan 1, 1989

Aqueous pressure oxidation at low temperature, although desirable from a process engineering and operating point of view, presents unique problems when temperatures approach 160°C (320°F). In developing the pressure oxidation process for the Lone Tree Mine, elemental sulfur formation and agglomeration with pyrite proved to be a problem. This paper discusses some of the unique features of the Lone Tree sulfide deposit and its amenability to low-temperature oxidation. Problems encountered during pilot plant operation and their solutions are discussed.

Jan 1, 1995

By Anthony G. Grice

This paper discusses the contribution that backfill is making to the Australian mining industry and provides some information on the largest operations together with some novel applications. Each of the three major backfill types; hydraulic, rock and paste are discussed in turn with a focus on new ideas and advances in understanding, technology and operating practices.

Jan 1, 2001

By Ben L. Seegmiller

INTRODUCTION Site characterization using oriented borehole core is the subject of this paper. Borehole core is a standard source of data for rock mechanics investigations. Oriented borehole core provides data whereby the geometric orientation of various geologic discontinuities (faults, joints, bedding, etc.) may be determined. The orientation and strength characteristics of discontinuities are important in many engineering investigations and in particular, in slope stability analyses. In heavily vegetated or soil covered situations, oriented borehole core may provide the only means of assessing the subsurface planes of weakness which characterize the site. The purpose of this paper is to briefly describe various methods or orienting core, core characteristics which may be logged and the methods of processing and using the data for site characterization.

Jan 1, 1977