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By M. Rotz

In the minerals industry today, the ?low hanging fruit? that once existed to debottleneck production and improve recovery, while meeting market needs for quality in mineral processing operations, are more and more difficult to find. Systematic methods for establishing plant mass flow, recovery, operational efficiency and control strategy in context with customer specifications provides the necessary insight and confidence for plant operators to prioritize improvement projects in order to maximize return on investment (ROI) for the site. The evaluation of aggregate and industrial mineral processing plants requires the following steps when projecting cost saving opportunities: collecting background data, conducting a base-line evaluation, analyzing specific unit-operation performance, defining investment options, prioritizing the selected improvement opportunities and the implementing process changes. The following paper describes the approach and challenges of developing an improvement plan for a dry and wet mineral processing operation.

Feb 23, 2014

By R. C. Woodhead

During past years the most difficult problem presented to the coal preparation engineer has been the cleaning of fine coal, The problem of handling fine coals is more involved than the coarser sizes, because the higher surface moisture contents complicate screening, and the larger percentages of fine near size material complicate separating problems. Low gravity high capacity specific gravity separations were not possible with equipment available at that time. Coal preparation engineers did develop machines that would effect a separation of the fines, however, to maintain a high efficiency, the point of separation had to be a relatively easy one. The more difficult separations were made in the coarse coal sections of the washeries, and the fines were generally cleaned at higher specific gravities in equipment such as tables, feldspar jigs, rheolaveurs, etc. Clean products from both processes were mixed, resulting in overall lower ash contents, During the last several years, however, we have been confronted with increasing demands ZGP more precise separations of finer coals to still further reduce ash contents. A study was begun and a program instigated to improve the cleaning of fine coal, The result of this endeavor was the development of the new cycloidal heavy medium cyclone.

Jan 1, 1964

By Alfredo Valencia-Toledo

This study delves into the satisfaction levels of indigenous communities in Apurimac-Cusco, Peru, concerning mining activities in their region. Our primary objective is to elucidate the interrelationships among observable variables, which are conceived as linear combinations of multiple factors. Employing the statistical methodology of exploratory factor analysis, we aim to pinpoint the pivotal factors influencing the progress of mining activities in Apurimac-Cusco. Through our analysis, we have identified eight key factors that exert a significant impact on mining’s sustainable development in the area. These factors encompass diverse facets, ranging from the support offered by mining company to communities, environmental considerations, education, economic factors, provision of basic services, transportation and communication, support for social organizations, and social-health-related aspects. This research endeavors to provide a comprehensive understanding of the complex dynamics surrounding mining activity satisfaction among the indigenous population, offering a basis for further exploration and policy development.

Feb 17, 2024

By Gerald Zink

The work described in this paper is sponsored by the Bureau of Mines for the purpose of accelerating the drilling of roof bolt holes and reducing the quantity of materials needed to fill each hole. A high-speed small-hole drill has been fabricated and tested in the laboratory. High priority has been given to safety, reliability, and compatibility with underground coal mining practice. The combination of drag bits and erosion jets is designed for high penetration rate, long wear life, and uniform hole size in a variety of sedimentary strata. A reliable high-pressure high-speed swivel feeds water to the bit at about 4 1/min (1 gpm). The duplex hydraulic intensifier which drives the jets has a 40 kw capacity (30hhp) Results of recent full-scale laboratory testing are presented.

Jan 1, 1978

By B. Strickland

The decision to accelerate development of Stillwater Mining's East Boulder Mine was made in March of 1998. It required the completion of conceptual designs by July of 1998. This was accomplished through teamwork and close cooperation of mine personnel, engineering firms and vendors, all working toward the common goal of developing an efficient and workable design. Early in the project, representatives of Stillwater Mining, Kilborn International, Parsons Brinckerhoff Transit and Rail Systems, Continental Conveyor, and H.A. Simons met to develop methods to bring the mine into production at a highly accelerated rate and to solve potential bottlenecks, including the movement of personnel, materials, and muck through a 5.6 km (3-1/2 mile) adit. This interaction, including companies not normally associated with the mining industry, led to innovative approaches and designs produced by Kilborn Engineering and Stillwater Mining.

Jan 1, 1999

By A. Gungor

Thermal treatment can significantly improve industrial comminution operations by reducing energy requirements and increasing mineral liberation. The assistance of thermal pretreatment prior to grinding by microwave heating is scrutinized in this study. For this purpose three copper ore samples with different chemical composition were used. To see the effect of microwave heating on ore; work index, breakage rate and breakage distribution functions of original and heat treated samples were examined. The results obtained in this study did not show significant improvement in the grindability characteristics of the studied ores with microwave heat treatment. The inadequate amount of microwave transparent matrix was the main reason for the absence of cracks and micro-fractures in the microwave heated copper samples.

Jan 1, 1999

By N. Rajmohan, K. T. Jacob

Presented is a thermodynamic feasibility analysis of extracting base metal chlorides from low-grade, multi-metallic oxide ores using CaC[1]2 as a chlorinating agent in the presence of SO2 and O2. The oxides react to form corresponding chlorides, while CaC[1]2 is converted to CaSO4. The Ellingham diagram is used for comparing the standard Gibbs' free energy change for the sulfation-chlorination reaction of a large number of oxides. Except for alumina, silica and chromia, most of the other metal oxides will be converted to their respective chlorides. The volatile chlorides can be condensed, and the chlorides present in the condensed state can be leached. A process is proposed that uses a nontoxic chlorinating agent and gives an efficient separation of the metallic values from the gangue.

Jan 1, 1993

By J. J. Renton

The iron disulphide minerals, pyrite and to a lesser extent marcasite, are ubiquitous to coal and coal associated rocks and are the source of nearly all the environmental problems associated with the mining, processing and utilization of coal. The iron disulphides as well as the other minerals in coal exhibit systematic spatial pat- terns of distribution on both regional and local scales and show predictable associations, most of which are determined by the geochemical-sedimentological controls under which they form. It is the purpose of this paper to discuss the geochemical-sedimentological conditions responsible for the formation of coal minerals with special emphasis on the formation of iron disulphides, to illustrate the regional and local patterns of mineral occurrence within coal, to present the microscopic associations of the iron disulphides and finally, to discuss the most important single environmental aspect of the iron disulphide content of coal and coal associated rocks; the production of acid mine drainage.

Jan 1, 1986

By C. R. Everly

"The purpose of this paper is to review the most effective methods of reducing chloride transfer and chloride removal in the solution extraction and electrowinning (SX/EW) process. Elevated chlorides in electrolyte have various negative effects including a reduction in current efficiency, increased handling costs at rod plants and smelters, increased anode corrosion, cobalt losses due to increased electrolyte bleed, degradation of HDPE piping, and increased corrosion in the SX/EW plants. Historical controls that Sierrita has used to control chloride transfer, in order of effectiveness, have been chloride gasification at the EW that is directly correlated to amperage and chloride concentration in electrolyte, wash stage bleed and efficiency, width and velocity of aqueous bands, and electrolyte bleeds. Maintaining high bleed rates and high amperage settings has been a challenge with decreasing pregnant leach solution (PLS) grades, so keeping chlorides out of the electrolyte has become imperative. The effectiveness of reducing aqueous entrainment, optimizing wash stage efficiencies, and improving organic quality to reduce the transfer of chlorides to the electrolyte are illustrated in this study. INTRODUCTION The transfer of impurities from PLS feed streams to electrolyte in the Copper Solution Extraction process is a very common problem and is the reason that the wash stage exists in most SX operations. The main impurities affecting the SX process are iron, chloride, nitrate, and manganese. Elevated chlorides in the electrolyte have various negative effects including reduced current efficiency, increased handling costs at rod plants and smelters, increased anode corrosion, increased cobalt losses due to increased electrolyte bleed, degradation of HDPE piping, and increased corrosion in the SX/EW plants. Freeport-McMoRan Sierrita Hydromet is unique in that a high-chloride byproduct stream from the molybdenum process is pumped into the SX raffinate solution pond. This byproduct steam accounts for the majority of chloride introduced to the circuit, and over the years has built up to a point where 4000ppm chloride is consistently in the PLS feed to the SX. Concentrations of chloride over 70 ppm in electrolyte will result in downgraded cathode, so it is important to limit chloride carryover from SX as much as possible. Historically, Sierrita has been able to manage chloride levels with reactive techniques including increasing electrolyte bleeds and rectifier amps. Decreasing copper in PLS has made high amps harder to maintain, and increasing bleed rates have a direct impact on production goals."

Jan 1, 2015

By E. A. Córdova

Current methods for scratching a piece of rock to obtain or check the characteristics of its component material can sometimes be expensive and time consuming. Scratching a rock core requires an object with a point that it is capable of sliding along the surface of the rock while recording the response from the rock due to the sliding. With the idea of providing a cost efficient solution for a scratch device, a new generation turntable arm, composed of a cartridge with a diamond stylus and a USB output connection to the computer, was used to record the vibrations from the sliding of the stylus along a rock core surface. The output sound from the stylus was captured with the computer as an audio input signal. The raw sound data was recorded in a standard waveform audio format (wav) file, and post-processed using sound spectrum analyzer software (Spectra-Lab) to capture numerical data such as frequency, amplitude, and noise from the file. The results for frequency, amplitude, and noise were compared and plotted against the scanned surface of the rock core in the search for correlations that might represent specific characteristics of the surface being scratched.

Jan 1, 2010

By T. Kelly

The Cannon Mine is located in Chelan County, near Wenatchee, Washington, at the eastern foot of the Cascade Mountains. The mine is situated about two miles from the Columbia River, in the arid Columbia River Valley. Two hydroelectric dams provide electricity for the area, the Burlington Northern Railroad has a switch yard and loading facilities in Wenatchee. Approximately 25,000 people live in the area. The principal industry is fruit farming. Underground mining techniques are used to provide feed for a 2,000 tpd flotation concentrator at the site. The techniques are low- cost, high productivity methods which allow for a high extraction rate along with a high rate of recovery of the minable reserve.

Jan 1, 1986

By Terrence Chatwin, Michael Sweeney, Steve Accardo

Sutter Gold Venture excavated an exploration decline into a mineralized zone in the Sutter Creek gold mining district. Delays in obtaining the conditional-use permit resulted in 7 to 10 million gallons of water accumulation in the decline containing elevated dissolved arsenic. Sutter received a permit to land apply the water after reducing the arsenic concentration to 0.05 mg/L. Initially the water was treated by co- precipitation arsenic with ferric hydroxide. Operational difficulties of this treatment system resulted in Sutter pursuing alternative treatment methods. The activated alumina adsorpting was selected due to its flexibility and ease of operation. Operating and maintenance data and costs will be presented.

Jan 1, 1995

By Lawrence Tsang, Conrad Ng, Tim Leung, Peter Poon

"The Mined Tunnel is part of the Central-Wan Chai Bypass and Island Eastern Corridor Link (CWB), which is a strategic road along the northshore of Hong Kong Island targeted to alleviate the heavy traffic congestion. The objective of this paper is to review the performance of construction of a 160m long Mined Tunnel with a trinocular cross-section area of 460m3 and a combined span of about 50m underneath the southern approach ramp of the existing Cross Harbour Tunnel (CHT) by sequential excavation method (SEM) in hard rock. Mechanical excavation of tunnel by adopting the New Austrian Tunnelling Method (NATM), together with the application of NGI Q-system allows observational approach and optimization of temporary rock support design. Furthermore, the good performance of optimized rock support and the stability of CHT are confirmed through instrumentation monitoring review. This paper also discusses the selection of different tunnel plant and equipment to achieve the planned rates of tunnelling by mechanical excavation in competent granitic rock. INTRODUCTION The works of the CWB mainly comprise construction of 4.5km dual three-lane trunk road, of which a 3.7km section is a tunnel connecting Rumsey Street Flyover in Central to Island Eastern Corridor at North Point (see Figure 1). The Mined Tunnel runs from the ex-Public Cargo Working Area (ex-PCWA), underneath the existing CHT, and through the Causeway Bay Typhoon Shelter. The Mined Tunnel passes at an oblique angle beneath the southern portal of CHT over a length of some 50m. CHT is the primary sensitive receiver of this project and is utilized with a daily throughput of about 120,000 vehicles that far exceeds the design capacity of 78,000 vehicles per day. Hence it is necessary to choose the most appropriate tunnelling method to preserve the structural integrity of the CHT. Other sensitive receivers in the vicinity include structures to the north of the Mined Tunnel, the Royal Hong Kong Yacht Club (RHKYC); and to the south of the Mined Tunnel, the Police Officers’ Club (POC)."

Jan 1, 2016

By J. D. Miller

"It is now possible to use 3D X-ray tomography analysis for plant-site characterization of coarse particles at a sampling rate of about 3 kg/min for particles which range in size from 150 mm to 1 mm at a voxel resolution of about 150 microns. This is quite a significant advance in X-ray tomography technology and should be useful for plant-site coarse particle characterization (size, shape, composition, density, texture, grain exposure, mineral liberation) with a response time of minutes after receiving the sample. Applications in the mineral industries are discussed including the coal industry, aggregate industry, metal mining and the processing of industrial minerals. INTRODUCTION Plant-site characterization of coarse particles at coal preparation plants, crushed stone/aggregate plants, and mineral processing plants is needed to improve plant capacity, product quality, and/or process efficiency. Not much on-line coarse particle characterization is done at these plants. Some limited information regarding particle size is obtained on-line from reflected light images using systems such as the OPSA, Split, and WipFrag analyzers. Even laboratory analysis of coarse particles has been difficult because of the large amount of sample required to insure statistical significance of the results. During the past decades laboratory 3D characterization of particles from energy and mineral resources by X-ray tomography has been demonstrated and used to good advantage [1, 2]. 3D X-ray tomographic analysis had its origin in the medical services industry; it is used to provide internal images of the human body and now has also been developed for non-medical applications [3]. Figure 1 shows a schematic diagram for the cone-beam geometry micro-CT system. In our case X-rays from a microfocus X-ray generator are partially attenuated by the sample (a packed bed of particles) that is made to rotate in equal steps in a full circle about a single axis of the particle sample. At each rotational position, the surviving X-ray photons are detected by a planar two-dimensional array (image intensifier) large enough to contain the shadow of the specimen. These two dimensional projection images are collected using conventional video technology. The video signal for each projection is then converted to a two-dimensional digital array by an image processing system. Finally, a three-dimensional image is reconstructed from the collected set of projection images. With the availability of automated high speed X-ray tomography [4] it now seems possible to do plant-site particle characterization at a sampling rate of about 3 kg/min for particles which range in size from 150 mm to 1 mm at a voxel resolution of about 150 microns. This is quite a significant advance in X-ray tomography technology and should be useful for plant-site particle characterization (size, shape, composition, density, texture, grain exposure, mineral liberation) with a response time of minutes after receiving the sample. Applications in the mineral industries are discussed including the coal industry, aggregate industry, metal mining, and the processing of industrial minerals"

Jan 1, 2016

By D. Spindler

Pursuant to the Federal Surface Mining Act of 1977 and the Illinois Surface Mining Act of 1980, Illinois has adopted revegetation success standard regulations that include the Agricultural Land Productivity Formula. The Formula establishes yield goals and standards to measure the success of meeting yield goals for reclaimed prime farmlands. The formula compares the quality of the pre-mining soils in the permit area and the county, to the crop production achieved on the reclaimed permit area and the county crop yield in a given crop year. The regulations also specify acceptable crops, erosion control requirements and time frames for demonstrating success.

Jan 1, 1986

By Jae-Chun Lee, Kang-In Rhee, D. B. Dreisinger, Hyo-Shin Yu, G. A. Kordosky

The development of a process for direct synthesis of very pure ZnO powders from zinc-bearing waste was investigated. The zinc waste which contains 55% zinc was leached with sulfuric acid. After iron removal by hydrolysis from this zinc solution, purification through solvent extraction by the use of D2EHPA as an extractant was carried out. Then, loaded zinc in the organic solution was stripped and precipitated simultaneously using oxalic acid as a precipitant. Synthesized ZnC2O4 precursors by precipitation stripping were calcined to obtain ZnO powders exceeding 99.9% purity. The effects of sulfuric acid concentration, leaching time, and pulp density on the extraction of zinc were studied and optimum conditions for the solvent extraction were obtained through purification of the zinc solution. The size, morphology, and size distribution of synthesized ZnC204 powders were studied in terms of oxalic acid concentration, temperature, surfactant added, precipitation time, etc.

Jan 1, 1993

By Gregory M. Rumbaugh, Todd R. Kostecki, Christopher Mark

The paper examines five massive pillar collapses in underground stone mines in the eastern United States from 2015 to 2021. These collapses caused significant airblasts, surface subsidence, and damage to mine infrastructure. The study identifies factors contributing to pillar collapses, such as slender pillars with width-to-height ratios of 0.8 or less, and proposes a framework for evaluating and mitigating collapse risks.

Nov 1, 2023

By LeRoy D. Loy

The coal mining industry must be able to compete with alternate sources of fuel for the utility and industrial customers. If the industry is unable to control transportation costs, either due to government interference, or for other reasons, then mining costs must be kept down. Australia, South Africa, Canada, (and later Colombia) will take larger shares of the export market if mining costs are not kept competitive. The government's environmental regulations must be met without incremental increases in mining costs. Entrepreneurial instincts must be retained by the industry to provide for their investment in the future. What are the Problems with Existing Research? Government funding for coal mining research has been reduced or virtually eliminated. BCR (Bituminous Coal Research) is now a membership- supported organization, but its primary focus has been on health and safety-oriented research. BCR, however, is now attempting to widen its scope and conduct other types of research. There are almost no funds in EPRI's (Electric Power Research Institute) program for coal mining research. Large mining companies do some research for their own purposes and needs, but this is proprietary and therefore results are not shared with the remainder of the industry. The mining industry as a unit is not undertaking productivity (systems) oriented research in any common or cohesive manner.

Jan 1, 1983

By Jürg Künzle

The use of the underground space has been a recurring issue in human history, whereas the reasons for building subsurface structures have changed over time. In the decades to come, the world will be marked by a variety of underground projects never before seen. This paper describes a series of characteristic challenges of designing and building underground freight transportation systems, with reference to the example of Cargo sous terrain, a privately funded underground logistics project in Switzerland. It provides an overview of contracting practices that allow these challenges to be addressed with success.

Jun 13, 2021

By Mollie Hunt, William Riley, Russ Downer, Kate Willa Brown Requist, Víctor O. Tenorio, Geoffrey Gill

One of the first activities after returning to the Moon will be finding sources of water and materials for the construction of human settlements and other infrastructure. There is evidence of the existence of deposits in the bottom of craters at the South Polar region and in flat areas around. Based on geological data from the Moon, a block model representing a deposit or icy regolith has been defined in the vicinities of Shackleton Crater, with unique characteristics of shape, thickness, and water contents. A mine plan utilizing surface mine modeling software for ore extraction from an open pit- type of excavation to a delivery point near a water processing facility is proposed, with monthly, quarterly, and yearly schedules. Production results, dashboard charts and progress of the topographic changes are also presented.

Feb 1, 2024