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By K. McG. Bowling

A statistically-designed exper¬mental study showed how gangue minerals, flux additions, fineness of grind, firing temperature and time affect the properties of acid pellets made from a Western Australian hematite ore. Alumina has less effect than silica and lime, but various interactions between the six variables occur, which influence abrasion index, reducibility and cold compression strength. Finer grinding has little influence on reducibility but improves the other two properties. The major variable is firing temperature. It interacts with all other variables in its effects on pellet properties. Calculations based on the data show the implications for straight-grate pellet plants and optimum hood temperature range.

Jan 1, 1980

By R. E. Williams

University of Idaho scientists research under U.S. Bureau of Mines Cooperative Agreement C0278001 constitutes a complex hydrogeological, hydrochemical and metallurgical mine waste management project at an existing Superfund site. Technologies that may prove useful for the extraction of dissolved metals from acid mine water and solid wastes include lixiviation and biosorption. Acid mine water is the major, long-term problem in the valley. We are attempting to delineate the major sources of ground water recharge which feed the acid mine drainage and their hydraulic properties. Grouting of recharge areas may facilitate minimizing the production of acid mine drainage if recharge pathways can be identified.

Jan 1, 1990

By Robert E. Frey

Regardless of the mechanical design features of a particular air classifier certain basic principles apply. Specifically , there are two forces at work: 1. An air drag force 2. An inertial or centrifugal force. The air drag force has an increasing influence as particles become smaller. A very small low mass particle is easily carried along with an air stream even when turning a corner. Thus, fine particles follow the air away from the classifying zone. Inertial forces increase as the mass of a particle gets larger. Thus oversize particles tend to obey Newton's laws and respond to centrifugal forces or simply continue in a straight path when the airflow changes direction.

Jan 1, 1985

By J. L. Francke

This paper describes the practices and methods used in a study of Time Domain Reflectometry (TDR) as an inexpensive deformation monitoring tool in underground excavations at the Waste Isolation Pilot Plant (WIPP). The WIPP is being developed near Carlsbad, New Mexico, for the disposal of transuranic nuclear wastes in bedded salt 655 m (2 150 ft) below the surface. Data collected from WIPP geomechanical monitoring are used to characterize conditions, confirm design assumptions, and understand and predict the performance of the deep salt excavation. The geomechanical monitoring program encompasses numerous geomechanical monitoring techniques ranging from inspection of observation boreholes to advanced radar surveys. In 1989 TDR was introduced as a monitoring tool with the installation of 12.7 mm (0.5 in) diameter TDR cables in the underground excavations. In 1993, a new TDR system was installed in a separate location. Based on experience with the previous installation, enhancements were implemented into the new TDR system that: 1.) extended the period of performance by increasing cable diameter to 22.2 mm (0.875 in), 2.) increased accuracy in locating areas of deformation by aligning cables with nearby observation boreholes, and 3.) improved data acquisition and analyses using a standard laptop computer, eliminating the chart recorder previously used. In summary, the results of a correlation between the TDR signatures to nearby observation boreholes and geomechanical instrumentation will be presented.

Jan 1, 1996

By Sukru Sumer

East Pit Lake is an artificially created lake that resulted from the remediation and reclamation of surface coal mining operations at TransAlta Utilities' Whitewood Mine in the Wabamun area west of Edmonton, Alberta. The original excavation resulted from the creation of a mine end cut at the northern extent of the mining operation. The area of the surficial drainage basin that feeds East Pit Lake was relatively small. Therefore, most of the inflow and outflow from the lake would result from regional ground water flow. There was a concern about the lake's ability to provide a suitable habitat for a sportfish population. To determine the final recovered water level and rates of recovery, a two-dimensional ground water flow model was used. Data supplied by nested piezometers in and around the mine were used to calibrate the computer simulation and assess predicted recovery.

Jan 1, 1995

By Issac Douglas, Sheila Devasahayam, John S. Thella, Manoj K. Mohanty, Jeremy Prishmont

The flotation performance of Sodium O, O-diisobutyl Di thiophosphate (referred to as reagent A) was compared with Aerophine 3418A (referred to as reagent B) for floating a complex copper ore grab sample (Ore A). Preliminary test results indicated a cumulative copper concentrate grade of 10.19% with a recovery of 86.31%, which was achieved with reagent A from a feed consisting of 5.32% Cu. The grade and recovery achieved using reagent B are 9.11% and 87.85%, respectively. A comparative analysis based on the preliminary test results indicated that reagent A’s performance is better than that of reagent B at lower concentrate grades, specifically below 12% Cu. However, the flotation performance is better for reagent B at higher concentrate grades (>12% Cu). A more detailed study was conducted to optimize the grade-recovery performances achievable from both reagents on a complex low-grade copper ore sample (Ore B) from Western USA. Test results indicated a copper concentrate with a grade of 5.5% Cu and 78.59% recovery was obtained with reagent A compared to 4.31% Cu and 62.04% recovery with reagent B from a feed consisting of around 0.25% Cu.

Feb 22, 2026

By Nelson R. Shaffer

Glamorous, burgeoning biotechnology and mundane industrial minerals would at first glance seem to share little in common, but in truth, modern biotechnology depends on many minerals. Biotechnical processes also can be used in industrial mineral extraction and processing. Biotechnology is broadly defined as the application of biological organisms, systems, or processes to manufacturing and service industries. Genetic engineering has reinvigorated one of mankind's oldest sciences, biotechnology, into a booming business. Many modern processes depend on microorganisms cultivated under very stringent conditions in bioreactors. Minerals from carbonate, sulfate, chloride, nitrate, phosphate, and silicate families are used to provide essential nutrients and to regulate growth conditions (such as pH) in order to assure optimal growth of organisms. Certain cells or enzymes perform better when immobilized upon or within solids, and minerals are often used to immobilize cells, especially in continuous process. Minerals are also used extensively in separating and purifying products of biotechnology. Diatomite, zeolites, and silica are especially useful in purification processes. Industrial minerals also are commonly used to clean up large volumes of process water that must be treated. Biotechnology can be employed in exploration, extraction, and processing of geologic materials and in reducing mining or other environmental problems through bioremediation. Microbes have been shown to solubilize certain elements and so promote extraction of heavy metals, phosphate, aluminum, potassium, and even rare earth elements. In a related technique, unwanted materials such as pyrite impurities can be leached microbially to produce cleaner products in sand and clay industries. Microbial actions can modify surface characteristics and so enhance certain ceramic properties. Certain organisms can accumulate useful elements from dilute sources; others can transform unusable chemical species to more useful forms. Deterioration of stone, concrete, and even glass or brick, can be accelerated by microorganisms. Control of such biodeterioration could improve long-term performance of industrial mineral products. Microbial processes have shown promise in improving several mine-related problems. Certain bacteria help remove clays from phosphate slimes and other suspensions. Others are used to degrade cyanide or other organic chemicals such as floatation aids. Cells immobilized on clays have been especially efficacious in bioremediation. Biotechnology industries, like the industrial minerals industries, encompass huge ranges of materials and processes. Costs of products from these industries range from pennies to thousands of dollars per unit, and their products are vital for maintaining modern life styles. Many biotechnical processes depend upon industrial minerals and certain biological processes can be harnessed to do useful tasks in the minerals field. The interplay of industrial minerals and biotechnology is important today, and as biotechnology advances, its interaction with the industrial minerals industry can only increase.

Jan 1, 1995

By Hou Xilun

Three production methods of rapid cold bonding and low temperature bonding pellets using sponge iron powder as a binder have been successfully developed. These methods differ from ordinary bonding method by no addition of salt and other catalyzers, no corrosion of equipment and no pollution of environment. Mechanism of pellet bonding is studied. Experiment shows that these pellets have good metallurgical properties. A semi-industrial test has proven the laboratory results, with the production of metallic pellets continuous and stable. These methods are substituted for traditional high temperature firing of oxidized pellets in direct reduction. As a result, the plant for oxidized pellets can be saved and substituted for grate in the grate-kiln system. Thus, 20% of the investment could be saved. Production cost may also be decreased. The production of cold bonding pellets does not need additional area.

Jan 1, 1980

By Joseph A. Dos Santos

Developed in 1983, high angle conveyors - HAC®s are proven versatile systems for elevating materials continuously from a lower to an upper level. Such systems may also be used to lower materials continuously. HAC®s have found commer­cial application in widely varying materials (including coal, refuse, coarse ores [-250 mm], hot clinker, municipal sludge, wood chips, gypsum, slag, excavated earth, various grains and RDF), at widely varying throughput rates from 0.27 to 4250 t/h. The conveying profiles have varied widely and elevating heights range from 3.66 m to 175 m. HAC®s have found application in coal, copper and iron mining, and preparation, in municipal waste treatment, rapid transit projects, pulp and paper mills, cement plants and in gold mining. While noting a wide variety of applications in general, the present writing focuses on Newmont Gold's HAC®, near Carlin, Nevada, which elevates very coarse gold ore to the screening plant. Additionally, upcoming HAC® applications in gold mining are discussed and a proposed multi-flight vertical HAC® system from a deep underground mine is described.

Jan 1, 1996

By W. Robert Rose, Randall Pyper, Carlos Mirabal, Jaime Eguivar

In 1984, work was started to determine the viability of heap leaching silver-containing waste dumps from Cerro Rico near Potosi - Bolivia, at an elevation of 4300 meters (14 100 it.). The result today is an unusual heap leach utilizing fine crushing, grinding, and agglomeration to process 1000 tonnes per day of ore containing 200 g/tonne silver. The unique metallurgical, economic, and political factors will be discussed which led to the decision to build a heap leach rather than a conventional agitation leach plant. Capital and operating costs will be given along with some of the uncommon process design and equipment problems encountered while developing the operation.

Jan 1, 1990

By J. J. Kellar, W. M. Cross, H. Du, C. D. Struckman, D. A. Boyles

Silane coupling agents have been used in the filler industry for years. One particularly unique feature is the ability of the coupling agents to enhance the adhesion between filler and polymer matrices. This paper will review the use of coupling agents for polymer matrix composite applications and discuss a new approach to coupling agent chemistry, namely, direct formation of a silicon-carbon non-hydrolyzable linkage between glass and coupling agent. The grafted silane monolayers were evaluated by infrared spectroscopy to ascertain their surface coverage and relative stability. Finally, composite specimens were fabricated and their mechanical properties were compared with traditional silane coupling agent treatment.

Jan 1, 2003

By Gordon I. McPhail, John D. Nelson

Tailings management represents a major portion of the cost associated with extraction of gold. For each gram of gold extracted, 150 to 200 kg of waste material is produced. Because of environmental concerns and unwillingness of society to accept environmental damage caused by poor waste management practices it has become essential to follow responsible and safe practices in tailings management. This paper presents general aspects of tailings management and discusses different techniques utilized. Characteristics of tailings and the effects that these have on stability and environmental aspects are discussed. The paper also discusses the effect of mine back-filling practices on the surface disposal of the remaining tailings fraction.

Jan 1, 1987

By John Carson

Belt feeders are commonly used to meter the flow of bulk solids from bins and hoppers. If the interface between the hopper outlet and belt feeder is not designed correctly, flow from the bin may be severely compromised, resulting in problems of no-flow, segregation, flooding, etc. By knowing the flow characteristics of the bulk solid being handled and applying proven design techniques, such problems can be avoided. Relevant bulk solids flow characteristics are identified, along with measurement techniques. Design procedures for correcting problems with existing feeders as well as proper design of new feeders are presented, along with case histories of successful application of these procedures.

Jan 1, 2008

By Adrian Brown

Groundwater inflow and impacts have become major aspects in the permitting and operation of many gold mines. First, the hydrothermal or placer genesis of many of the orebodies being investigated or produced today almost guarantees that mines will be "wet", involving groundwater control as part of operations. Second, the style of ore deposition a1 so often involves a1teration of the host rock, resulting in relatively weak, low permeabi1ity materials that require extensive groundwater pressure control for stable mining. Third, the location of many mines in arid areas guarantees that impacts on water resources will be matters of key focus during permitting and operation. However, groundwater control and protection is a technically difficult area and often involves managerial decisions and activities that do not fit comfortably into traditional mining. In an attempt to overcome some of these difficulties, this paper provides a guide to mine managers and hydrologists as to appropriate strategies for designing, setting up, operating, and evaluating groundwater programs at gold mines that get the job done and are cost effective.

Jan 1, 1988

In late 1993, Inco Ltd. completed a $600-million environmental improvement project at its Sudbury, Ontario operations -the largest single environmental project ever undertaken by a Canadian corporation. Efficient new facilities and innovative technologies installed during the course of the project have also significantly improved Inco's productivity and competitiveness. In early May 1994, a panel of 18 Inco authors contributed to a Technical Forum, "Environmental Programs at Sudbury," presented at the 96th Annual General Meeting of the Canadian Institute of Mining, Metallurgy and Petroleum (CIM) in Toronto. Their papers have been published in CIM's Toronto `94 Proceedings Volume, pp. 62-77. The following report draws primarily on discussions of Inco's milling and smelting operations published in the Proceedings Volume. The Proceedings Volume also includes papers on the acid and oxygen plants and on engineering, construction and commissioning of the project. The 222-page Proceedings Volume is available from CIM, $C27 plus shipping. To order, contact: V. Ward, CIM, Xerox Tower, 1210-3400 de Maisonneuve Blvd W, Montreal, Quebec, Canada H3Z 3B8; phone 514-939-2710, fax 514-939-2714. Lane White, Publisher.

Jan 1, 1994

By N. S. Tanious

This paper summarizes the results of an investigation into possibly the largest coal pillar failure in the USA. The newly opened drift mine is located in Southeastern Kentucky and worked an 11 feet thick coal seam, all other mines in the District worked seams 4-5 feet thick. The initial mine development consisted of 14 main entries (Fig. 1) which were driven in two sets of 7, under increasing depth of overburden. As the left seven entries came under deeper overburden the pillar ribs began sloughing which caused many of the concrete-block ventilation stoppings to crack. The mine management stopped the advance in the left seven and continued with the right seven entries. During the spring of the following year development resumed in the left seven, rib sloughage occurred again and this time severely cracked many stoppings and many were totally disintegrated from the excessive deformation. Within few weeks the sloughage was so heavy that many of these entries behind the active face were filled with piles of sloughed coal slabs. When the face reached a depth approximately 1150 feet, the sloughage became a slow, massive squeeze. The entry convergence (closure) reduced their height from 11 to 7-8 feet and the squeeze spread back to shallower depth covering an area roughly 300 pillars.

Jan 1, 1989

By Saurabh Kundu, Shakuntala Tudu, Indrajit Paul, Chandra Sekhar, Manikanta Nallamilli, Shaik Mahaboob Basha, Neha Gupta, Srinivas Dwarapudi, Dhiraj Madhukar Kadhe

Iron ore pelletizing using compressive and shear action on wet mixture feed has been studied. The physical properties, namely, moisture content, drop strength, green compressive strength (GCS), dry compressive strength (DCS), porosity, and cold crushing strength (CCS), have been studied. Pelletizing tests were carried out on four different types of ore, namely, hematite ore, magnetite ore, goethite ore, and sinter return fines. The inference of shear forces on silica distribution index in dry pellet has been studied using optical and scanning electron microscopy. Significant improvement in physical strength was observed due to compressive and shear forces on the pellet mixture feed. However, decrease in moisture content and ball porosity has been observed. Silica distribution index improved by 1.72 times for hematite ore, 1.47 times for magnetite ore, and 1.68 times for goethite ore. It has been found that bubble cavity has been reduced which is good indicator in terms of physical properties.

Jan 29, 2022

By Yuexin Han, Mu. Yufan, Yanjun Li, Peng Gao, Yongsheng Sun

"The objective of this study was to evaluate the effect of reduction temperature, reduction time and binary basicity on the size of metallic iron particles in coal-based reduction products of an oolitic iron ore. The particle size distribution behavior (i.e., cumulative passing percentage and mean size of metallic iron particles) during reduction was investigated in detail. Results showed that the particle size distribution of metallic iron particles was strongly influenced by reduction temperature, reduction time and binary basicity. The cumulative passing percentage and mean size significantly increased with reduction temperature and time in the entire range of the experiments. All curves of cumulative passing percentage versus particle size under different conditions demonstrated a similar trend (continuous increase). The size distribution parameters and mean size slightly increased with increasing binary basicity and significantly decreased when the binary basicity exceeded 1.0. The size of metallic iron particles could be controlled by adjusting the reduction conditions during coal-based reduction.IntroductionThe increasing demand for iron ore coupled with diminishing high-grade iron ore reserves has resulted in the urgent need for innovative technologies in order to use refractory iron ores. Oolitic iron ore is a typical refractory iron ore with tremendous abundance globally. Based on published literature, oolitic iron ore reserves are approximately 140 million tons in Europe, 10 billion tons in China and 66 million tons in Pakistan (Kazmi and Abbas, 2001; Wu et al., 2011; Yu and Qi, 2011; Sun et al., 2013a). Therefore, the efficient exploration and use of oolitic iron ore resources can play a significant role in easing the mineral resource crisis in the iron and steel industry. However, oolitic iron ore cannot be effectively upgraded by traditional beneficiation methods due to its mineralogical characteristics (e.g., low grade of iron, poor liberation of iron minerals and high phosphorus content) (Li et al., 2011b; Sun et al., 2013b).Researchers recently proposed coal-based reduction followed by magnetic separation to recover iron from refractory iron ores (especially oolitic iron ore) and a certain degree of breakthrough was achieved in both theory and practice. In this technology, iron minerals in the ore are directly reduced by coal to metallic iron, which grows into particles of different sizes. After comminution and liberation, metallic iron is concentrated by magnetic separation (Srivastava and Kawatra, 2009; Sun et al., 2013a; Li et al., 2011b; Sun et al., 2013b; Li et al., 2011c; Gao et al., 2013). Sun et al. and Gao et al. used this technology to examine the recovery of iron from oolitic and Bayan Obo iron ores, respectively (Sun et al., 2013a; Li et al., 2011b; Li et al., 2011c). Metallic iron powder with more than 90% iron content was obtained as the final product, which could be used directly in steel production."

Jan 1, 2015

By R. Y. Wan, Corby G. Anderson, L. Ernest Krys, M. C. Fuerstenau

Since 1942, refractory precious metal concentrates at the Sunshine mine have been processed for antimony metal recovery using a novel leach-electrowin method. This is counter to most antimony production facilities where pyrometallurgical techniques are usually relied upon. The key step for removal of the antimony has been an ambient pressure alkaline sulfide leach. In 1990, a comprehensive laboratory study was undertaken to better understand this process. Factors studied included temperature, agitation, concentrate regrind, alkaline species concentrations, sulfur species concentrations and solids concentration. Details of these studies, as well as a brief description of Sunshine metallurgical processes, will be presented.

Jan 1, 1993

In this paper, response surface methodology was applied to optimize the experimental conditions for the wet grinding of synthetic rutile. The effects of parameters such as rotation speed, solids concentration and duration of grinding on grinding efficiency were systematically investigated and the process conditions were optimized, using a nonlinear regression model based on central composite design. The statistical analysis of the results showed that in the range studied, the grinding efficiency of synthetic rutile was significantly affected by the rotation speed of the conical ball mill. According to results from analysis of variance, the value of the determination coefficient (R2=0.9989) indicates that the predicted values are found to be in good agreement with experimental values. The optimized experimental conditions were as follows: a rotation speed of 350 rpm, a solids concentration of 27.31% and a grinding time of 50.31 min, respectively. Under optimum conditions, the predicted grinding efficiency of 94.79% is obtained. The experimental values from the validation experiments were well within the predicted value of the model.

Jan 1, 2011