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By U. Schoepf

Economic and at the same time environmentally acceptable mining of small vertical ore bodies and veins to great depths has always been a challenge for miners. The Bauer cutter system, widely used in civil engineering, has been further developed for applications in exploration and mining, to a sustainable system for selective mining with a focus on small vertical ore bodies and veins, as well as residual ore in open pit operations. Current situation of conventional mining of small ore bodies and vertical veins Small ore bodies and vertical or near-vertical ore veins often pose a challenge to the mining industry. The relatively small size of the ore deposit over great depths or lengths, with only limited exposure to the surface makes economical mining difficult. Open pit mining of such ore bodies must either be terminated early because of the high stripping ratio and the enormous environmental impact or is unprofitable from the very beginning. The required massive stripping of waste rock leads to high material hauling times and costs, intensive roadway and bench construction and maintenance, possible safety hazards due to heavy vehicle movement, pit wall stability risks, intensive surface water management and massive waste dump requirements. In addition, it can be assumed that increasingly extensive rehabilitation measures will be required in the future after mine closure. Particularly in vertically oriented magmatic and hydrothermal deposits the technical, economic and environmental limits for further pushbacks, to extend the open pit depth, can lead to an early end of mine life even if a significant quantity of residual ore is left behind. Going underground is only a viable option in a limited number of mines with very high ore values and volumes. The high development cost of an underground mine, as well as the higher underground mining costs, often prevent further mining to greater depths.

Feb 1, 2023

By Haydn H. Murray

The area from Ohio on the east, Tennessee on the south, and Minnesota on the west: contains some very unique and useful clay deposits. Included are fireclays and plastic clays in Ohio, Kentucky, Indiana, Illinois, and Missouri; flint clays in Kentucky and Missouri; ball clays in Kentuckv and Tennessee; adsorbent clays (fuller's earth) in Missouri, southern Illinois, and Tennessee; and alluvial clays and shales for structural clay products from every state. Unique kaolin clays are known in Minnesota, Missouri, and southern Illinois and halloy-site localities are known in southern Indiana. The geology, physical properties, and uses or potential uses of these midwestern clays are described.

Jan 1, 1980

By James A. Jessop

The Bureau of Mines is investigating the use of geophysical methods to determine rock mass characteristics, particularly rock quality, lithology, and fracture parameters that are important for determining the feasibility of in situ leaching operations. As part of this research, two Bureau-developed crosshole geophysical systems are described that can be used for site investigation and rock mass characterization. Results are given for performance tests at field sites in Arizona and Texas and for correlations between the crosshole seismic data with fracture frequency, rock quality, and lithologic variation. Recommendations are made for using elastic waveform propagation characteristics and dynamic elastic properties for improving rock mass characterization in the geomechanical assessment of in situ leaching deposits.

Jan 1, 1990

By Daniel Hodouin

Artificial neural networks (ANN) are of growing interest in a wide variety of applications. Pattern recognition, speech processing, financial analysis, signal processing and process control are at present the most successful ones. This paper is an attempt to illustrate the potentiality of ANN applied to mineral processing. An introduction to the technology of ANN is first proposed to describe the various components and to explain the various phases encountered in setting up a network. Then examples are given to illustrate the use of ANN dynamic modelling of mineral processing units or plants and in process control.

Jan 1, 1991

By Ernest Hucke

This paper will cover basic pneumatic and electronic sensors, transducers, transmitters and their application in the Mining Industry.

Jan 1, 1965

By G. L. Ploetz

The lanthanon compounds are becoming increasingly more important for ceramic and allied applications. As the supply increases and the cost decreases, further development of these interesting materials will undoubtedly lead to new applications and an increased demand. Recent improvements in separation processes have lead to high purity in the individual lanthanon oxides. This report includes short discussions on the mineralogy of the ores as raw materials, and on the separation processes required to produce the pure individual lanthanon oxides in useful quantities. To discuss the presently known applications of lanthanon oxides, this general review is divided into the following categories: A. Glasses, Glazes, and Porcelain Enamels. B. Refractories and Abrasives. C. Electronic Ceramics. D. Nuclear Ceramics.

Jan 1, 1960

By NARAYAN K. BHAGAT, ARVIND K. MISHRA, Aditya Rana, M. M. Singh

The paper presents an innovative directional controlled blasting (DCB) technique for excavating unstable slopes along the Konkan railway in India without disturbing the traffic. New empirical formulae for small geometry blasting to estimate burden and throw were developed. A unique sequence of firing and excavation with powder factor varying between 0.04 and 0.39 kg/m3, irrespective of the actual free face, was used for rock blasting. The process controlled the throw of blasted material over the track and resulted in a smooth and stable wall. The slope angle was changed from 80–82 to 45–47 degrees, and possible wedge, planar and toppling failures were eliminated. No incident of rockfall and slope failure along these slopes has been observed after the stabilization.

By Yong Pan, Srivatsan Jayaraman Sridharan, Purushotham Tukkaraja

Block cave mining method poses unique ventilation challenges compared to other underground metal mining methods. This research study focuses on assessing the airflow behavior in regulated airflow distribution systems by developing a 1:100 scaled block cave experimental model and a numerical model. This study also investigated gas flow behavior under various airflow conditions. Based on our findings, we observed that reduction in particle size and porosity of caved materials, decrease in cave footprint, and closure of undercut drifts would increase cave airflow resistance. The increased airflow is found beneficial for gas dilution regardless of its source locations, while the regulated airflow distribution system might deteriorate gas dilution situation when the source is located in the extraction drifts.

May 12, 2022

By Jürgen Kretschmann

According to the model of product life cycles, the global coal mining industry is in the stagnation phase. The coal demand of the main consumer, China, has peaked in 2013 and is slowly declining. The Norwegian sovereign wealth fund, the world’s largest, has excluded coal-related companies for ethical reasons. Important players like the UN or the EU have already begun to describe pathways towards decarbonization. Increasing competition between coal mining companies and the mining regions can be expected worldwide if companies want to keep their positions on the global and national coal markets. Companies will focus on the best deposits. European countries like France, Spain, or Germany are only forerunners of this development—their centuries of coal production have been finished. The concept of sustainable development (SD) is fundamentally based on a model of progress where ecological, economic, and social dimensions should be developed equally and positively. But without the idea of competition, the concept of SD is incomplete. Questions arise, such as how can SD be realized on stagnating or declining markets without guarantees for companies “to live forever”? How can SD be a corporate goal in a phase of decline? How can declining mining regions sustainably progress into a better future? The German hard coal mining industry’s lifecycle has ended in 2018 after 60 years of stagnation and decline. As of 2019, all hard coal consumed in Germany will be imported, especially from Colombia, Russia, and South Africa. What has been done in Germany to handle the coal decline in a sustainable way and the lessons learned from this process is described in this paper. It may be useful for mining regions who will face a similar future sooner or later.

The vast coal resources of North Slope, Alaska can be expected to attract substantial interest because the nearly flat lying coal beds of the coastal plan are specially amenable to surface mining. Mining on a scale large enough to justify coal development in this area could have severe environmental effects. The mitigation would be uncertain because large scale coal mining and reclamation operations have not been carried out in the arctic The deficiency of the scientific data base is another factor that requires consideration if coal mining has to develop in accordance with the objectives of PL 95-87. The objective of this paper is to establish the interrelationship between the problems due to permafrost and factors in reclamation of post mining land in order to find ways to transform nature in a rational and purposeful manner and to suggest specific reclamation approaches that may be appropriate in this region.

Jan 1, 1986

By Jr. Raleigh

In a cooperative agreement between the U.S. Bureau of Mines and the U.S. Department of Energy, laboratory column-flotation tests were conducted to evaluate fluorosurfactants as selective fine coal flotation collectors. A Middle Kittaning seam coal responded to flotation with both anionic and nonionic fluorosurfactants. These fluorosurfactants were no more selective than MIBC alone. However, for increasing coal yields, nonionic fluorosurfactant systems did not increase total sulfur and ash contents as sharply as MIBC systems. Flotation selectivity also improved slightly when a combined anionic fluorosurfactant-MIBC system was used in acidic pulps (pH < 3.6). While the fluorosurfactants examined will not likely have direct application in current coal flotation practice, other fluorosurfactant systems could eventually prove beneficial for floating fine coals.

Jan 1, 1990

By D. W. Park

Longwall mining is considered the most efficient underground coal mining technique in terms of coal extraction ratio, production rate, and safety standards. Due to the increasing demand for higher coal production, wider panel and faster face movement have become the recent trends. Thus, longwall mining can create unexpected threats such as roof falls, excessive face convergence, shield damage and numerous maintenance problems causing sudden interruption of coal production and serious safety hazards. A recent study at the University of Alabama is dedicated to develop LoSCoMS (Longwall Strata Control and Maintenance System) which integrates real-time shield monitoring, data presentation, analysis, forecasting, and warning modules. The main objectives of this system is to provide the stability and maintenance information, at every minute, such as high load, low setting pressure, leg leakage, etc., analysis of various mining and geological parameters to determine past and present roof characteristics and forecasting of loading patterns for the following mining cycles, next periodic weighting, etc. Using this unique system, mine operating personnel are well aware of past, present and future roof loading patterns at the longwall face, and thus, proper safety measures can be taken ahead of time.

Jan 1, 1997

By A. John R. Hart

INTRODUCTION In each given set of operational criteria for tunnel design, ground conditions dictate the selection of the most appropriate construction method and tunnel lining. The designer has the responsibility to choose or restrict the choice of the tunnel lining to insure that the final solution provides a cost-effective permanent construction which will require the minimum of maintenance and endure to the benefit of future generations. This Paper deals with some of the aspects of precast concrete tunnel linings, their history and development through the years. It does not purport to be a comprehensive review of all that has ever been tried or developed but, hopefully, a starting point to encourage discussion and development for the future. BOLTED LINERS As a result of anticipating a shortage of cast iron tunnel lining in 1936 when work was proceeding on London Transport&apos;s Central Line Metro, a design for the precast reinforced concrete bolted lining was born. The design took the form of the traditional cast-iron lining but with substantial concrete stiffeners to take the shield ram forces. This new lining was used to construct some 14,000 feet of running tunnel using a ring width of 1&apos;8" which was the standard cast-iron width of the time. (Groves, G.L., 1943)

Jan 1, 1987

By R. B. Krog

The use of belt air as an intake source at longwall operations has changed greatly over the past decades. The practical considerations for the use of belt air are controlled by a variety of factors, including airflow quantity and velocity, coal methane content, methane desorption rates, coal mining rate, belt length, stopping leakage and the number of gateroad entries. At longwall operations, the advantages and disadvantages of belt air are different than for gateroad development and longwall panel extraction. During gateroad development, the use of belt air to ventilate the working section will reduce the leakage from the intake to the belt compared to the belt air being ventilated outby the working sections because of lower pressure differentials. A greater quantity of airflow will reach the last open crosscut with the belt on intake than outby, given the same amount of pressure and airflow available at the mouth of the section. This paper will investigate the current ventilation practices regarding the use of belt air during gateroad development and longwall panel extraction. Operating considerations regarding air quantities and pressures to deliver the required airflow will be investigated using ventilation network modeling.

Jan 1, 2010

By R. J. Kolada

The ventilation systems of coal storage silos are normally capable of rapidly dispersing any accumulations of methane in the atmosphere above the coal pile surface. However, the results of an investigation which is presented in this report show that hazardous concentrations of methane can accumulate within the coal pile. Methane trapped within the coal pile is released into the atmosphere of the loading gallery when coal is discharged from a silo. If the methane released is of a flammable concentration it is necessary to ventilate the gallery to reduce the risk of an ignition. This report proposes a simple test, which, after further investigations may prove to be an effective method to calculate gallery ventilation requirements.

Jan 1, 1985

By Michael J. Mankosa

Increased emphasis has been placed on recycling consumer and industrial waste products. This trend has created a new industry that is focused on recovery/ separation of byproducts from waste material. As a result, interest has increased in the development of separation systems designed for the recycling industry. Much work has been done in this area. However, existing techniques developed for minerals beneficiation are often ignored. An example of is the foundry industry. There are currently more than 3,000 foundries in operation throughout the United States. Each consumes between 9 and 900 t/d (10 and 1,000 stpd) of sand for mold production. Either silica, chromite or zircon is, used in various combinations with chemical or clay binders. After casting, the sands are typically discarded into a landfill. This practice has become an environmental concern, especially the disposal of chromite and zircon. Silica sand is not environmentally sensitive. But it is used in greater abundance (6 to 7 Mt/a or 6.6 to 7.7 million stpy)and thus has prohibitive haulage and landfill costs. Current technology for sand reclamation involves thermal treatment to remove residual binders followed by dry mechanical attritioning (Leidel, 1993; Klein, 1994). This approach results in high losses due to fines generation and high costs associated with thermal treatment. As a result, this approach has shown only limited success. Stringent regulations are also affecting the disposal of secondary materials, such as plastics and metals. This is particularly true for the ferrous and nonferrous scrap metal industry. It plays a major role in industrial recycling of steel, aluminum and copper. Applications such as wire recycling present challenging problems since a hazardous byproduct (plastic insulation) is generated by the recycling.

Jan 1, 1997

By A. Martikainen, S. GYAMFI

Luossavaara-Kiirunavaara Aktiebolag’s (LKAB) Konsuln iron ore mine, located just south of the famous Kiruna iron ore mine in Malmfälten in northern Sweden inside the Arctic Circle, was developed as a test mine between 2018 and 2020 for the Sustainable Underground Mining (SUM) project [1]. Besides functioning as a test mine, Konsuln also contributes to ore production. The existing mine ventilation system was designed for the current production rate of 0.8 Mtpa using conventional diesel machines. The design was created by Kiruna mine ventilation team, Stina Klemo and Joakim Jonasson, in cooperation with a consultant, Tomas Bolsöy from EOL Vent Mining AB. There is a plan to increase this rate to between 1.8 and 3 Mtpa in the future, and this requires the primary fans to be upgraded. Therefore, a study was carried out to determine whether using ventilation on demand (VOD) could avoid this fan upgrade and reduce Konsuln’s ventilation and heating power costs in the future. The study also investigated whether using battery electric vehicles (BEVs) along with VOD or as a standalone strategy could further reduce these power costs. In addition, the study analyzed the suitability of heating power reduction strategies presently or previously used in Nordic countries and Canada to investigate potential additional strategies to reduce heating power cost, the largest portion of Konsuln’s ventilation and heating power costs.

By William Gleason

"While the American Exploration & Mining Association (AEMA) was preparing to close one chapter and begin another during its annual conference in Spokane, WA Dec. 3-7, word of a significant victory on an issue that has been important to the association for many years came from the halls of Washington, D.C.During a keynote address on Dec. 6, Joe Balash, assistant secretary of Land and Minerals Management for the U.S. Department of the Interior (DOI), told a sold-out lunch crowd that the DOI had released final drafts of proposed revisions to the Obama-era greater sage grouse conservation plans. The revisions suggest removing hundreds of thousands of acres of federally protected habitat in Utah, and easing restrictions on energy development and other activities, including mining, in Colorado, Idaho and Wyoming.The protections of the sage grouse were put in place by the Obama administration in 2015. The sage grouse, a prairie fowl, is considered by conservationists to be a key indicator species for the health of America’s sagebrush ecosystem. The previous plan to protect the ground-dwelling bird imposed restrictions to development in sage grouse habitat, but did not place the birds on the endangered species list — a move that many believed would have imposed far more rigid rules.AEMA, and its executive director Laura Skaer, led the way in the fight against the Obama-era greater sage grouse plan, arguing that the plan unnecessarily hurt economic development.“We were the first organization to point out that the greater sage grouse was being used to stop mining, oil and gas production and grazing on public lands in the interior mountain west,” said Skaer who is retiring from AEMA with a significant legal win on this front. “Early on, we cautioned that the proposed Land Use Plan Amendments would be worse than a listing (of the sage grouse) under the Endangered Species Act. Very few believed us until they saw the plans with all of the restrictions and the recommendation for a 4-million-ha (10-million-acre) withdrawal from mineral entry. We were the only organization that filed comments on all 88 Land Use Plan Amendments in 11 states covering more than 24.2 million ha (60 million acres).”"

Feb 1, 2019

By Qiong Wu, Qinghua Gu, Yichuan Lv, Jin Yuan, Caiwu Lu

"The cut-off grade is one of the important parameters of mining production. Different material cut-off grade is directed to different destinations. Based on reasonable and optimal cut-off grade, long term mining plan and investment decision analysis can be made for mining managers. In view of multiple-metals open-pit, the paper has proposed that multiple-metals cut-off grade optimization model is set using the objective function to maximize net present value (NPV). The method of equivalent coefficient calculation is proposed to convert multi-metals cut-off grade optimization to a single metal cut-off grade optimization. Then the optimization model is applied in a molybdenum and tungsten large open-pit mine in china. The parameters of concentrate price are calculated by PRT in the model and the curve of grade-recovery rate is analyzed and studied according to actual production data. Based on 3D metal deposit model, the distribution of grade-tonnage is analyzed. At final step, an optimal cut-off grade is proposed to guarantee to maximize NPV. The example shows that the model of multiple-metals cut-off grade optimization can provide reasonable analysis for optimal multi-metals cut-off grade and develop optimal production strategies. Introduction Cut-off grade is one of the most important parameters in metal ore mining because of its influence on the overall economic profit of mining production. Along with the development of the mining production, dynamic optimization of cut-off grade is necessary through the analysis of technical economy. It is better to manage the mining production according to the variation of market. The cut-off grade plays an important role in mining production."

Jan 1, 2017

By CADEN VITTI, Barbara J. Arnold

Mine tailings, the byproduct of mining and mineral processing, are increasingly mass-produced as a result of increased demand for metals and minerals as well as the advancement in technology that allows for the exploitation of lower-grade ores. Lower grades can increase the volume of tailings that may contain new gangue minerals that should be evaluated for the presence of critical minerals and other valuable metals. The practice of reprocessing, while relatively new, is crucial to reducing environmental damages, obtaining valuable critical minerals from waste, and contributing to more sustainable repurposing and disposal methods. With the increase in tailings dam failures in recent years, there is a large motivating factor in remining and removing the potential hazard to benefit the safety of potentially impacted communities. In analyzing the perspectives of various domestic and international studies, this literature review will determine the feasibility of reprocessing and reutilizing mine tailings waste for a more sustainable future while exploring current practices that have benefitted ecosystems and communities.