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By Nancy Bingham

The mining industry’s image is molded by what the public knows, or thinks it knows about mining. As Caterpillar prepared for the production of its educational video, Common Ground, the public’s perceptions about mining needed to be established. Before we could educate people about mining, we had to find out what they already thought. As those perceptions were analyzed, we were able to narrow the video’s focus to relevant, realistic approaches. We found out what people did not know about mining. And, most importantly, facts they should know were singled out - facts that could create more favorable attitudes. This research was instrumental in the final direction of the Common Ground project. What the public believes As these perceptions about mining were researched, it was found that the beliefs of the general public are dominated by four concepts. Quotations from interviewees are included with the discussion of each of these concepts. Figure 1 shows an overview of people’s beliefs before education.

Jan 1, 1994

By V. O. Tenorio, K. P. Hague

Mines are constantly trying to improve production processes by optimizing work cycles, reducing operational delays, minimizing costs, controlling equipment utilization, and preventing occupational hazards. Currently, advances in digital mining technologies within the concepts of 5G and Industrial Touch Internet are allowing better control and monitoring of underground mining equipment, with centralized control systems that unify data analysis for proper decision making. A wireless 5G-based platform for controlling and monitoring systems for underground mine operations can be designed over a comprehensive layout in where bandwidth selection, sensor location, Wi-Fi repeaters and power distribution are put together to build a successful supervisory system. In order to confirm the validation of these concepts, a case study is proposed for a medium-sized underground mine with a multi-level network which includes tablets managed by production supervisors, along with other data collection devices installed in semi-autonomous mining equipment, collecting, and distributing data in near-real time, with interconnection to support and services areas on the surface.

Mar 2, 2022

By R. A. Bauer

Investigations of bedrock within subsided areas over abandoned coal mines in Illinois reveal very little disturbance of the bedrock. In areas that have surface subsidence of 0.3 to 1 m (1 to 3.25 ft), examination of cores from exploration drilling and investigations of the boreholes by means of closed circuit television have shown that fractures are spaced at least 0.9 to 3.6 m (3 to 12 ft) apart. They are located within a zone 6 to 15 m (20 to 50 ft) above the collapsed area in coal mines 42.6 to 112.7 m (140 to 370 ft) deep. The dip of the fractures ranges from 25° to 60°, cutting across nearly horizontal sedimentary bedding planes. The amount of fracturing found in the collapsed area decreased as the amount of soft, weak materials increased in the immediate overburden of the mine.

Jan 1, 1987

By Eugene F. Casey

The next ten to fifteen years will be exciting ones for the construction industry because three city agencies alone have started or will start, on tremendous expansion programs, the cost of which will exceed a total of four billion dollars. The major portion of this work will be done by the use of tunnelling methods. *Tunnelling is construction by any method of a covered cavity of predesigned geometry whose final location and use under the surface, whose cross-sectional area is greater than two sq. meters. The New York City Transit Authority's expansion program will provide for approximately 52 miles of new subways. The Board of Water Supply has already started on City Tunnel No. 3 which, when completed will provide the City with enough water until the year 2000, and the Board of Water Resources has embarked on a tremendous program to clean up the surrounding waters. Yes, these will be exciting years, particularly when one reads about the new novel exotic methods of rock breaking and disintegration, coupled with the new methods of soft ground tunnelling.

Jan 1, 1997

By Richard L. Patterson, Alan P. Finch

Twenty years ago, when tunnel projects in the UK were generally procured by the public sector, many were completed late and over budget. Now a significant proportion of new infrastructure is developed by the private sector. Seeking more certainty in cost and programme, promoters have tried new and radically different methods of procurement and contract forms. The paper will review these developments, then examine the approach adopted for some of the largest current UK tunnelling projects (both in the public and private sectors) including the Channel Tunnel Rail Link, the Heathrow Terminal 5 Development and new highway tunnels.

Jan 1, 2003

By S. J. Schatzel, K. M. Ajayi, E. N. Rubinstein, Z. Khademian

This study simulates the impact of a shale gas well casing breach near a longwall mine. Field studies are conducted to measure mining-induced permeability changes over the abutment pillar of a longwall mine, and a geomechanical model is developed in 3DEC, a three-dimensional numerical modeling code, to predict the aperture of fractures in the overburden at the study site. The predicted aperture values are used to determine mining-induced permeabilities, and the results are compared with the field measurements. These aperture values are provided as inputs into fracture flow code (FFC), which generates a stochastic discrete fracture network (DFN) model for the study site and predicts the potential shale gas flow to the mine. Results from 100 DFN realizations are statistically analyzed using the bootstrapping method to compensate for notable variation in fracture geometry. The results show a significant difference between the gas inflow for nearby panels due to increase in the induced permeability during mining of the second panel. The average gas flow to the mine was calculated as 4.72 × 10 m3/s (49 cfm) for a hypothetical breach at the Sewickley horizon during the first panel mining, 8.97 × 10 m3/s (19 cfm) for a hypothetical breach at the Uniontown horizon during the first panel mining, 2.16 × 10 m3/s (458 cfm) for a hypothetical breach at the Sewickley horizon during the second panel mining, and 8.07 × 10 m3/s (171 cfm) for a hypothetical breach at the Uniontown horizon during the second panel mining. Depending on the mine ventilation system, this could result in methane concentrations exceeding regulatory limits. Hence, these findings provide insights into the potential risk of an unconventional gas well casing breach near a longwall mine under shallow cover.

Feb 1, 2024

By Thys B. Johnson

This paper presents a new algorithm for solving the Controlled Flow Mine Ventilation Problem in an optimal manner - minimum power consumption. The use of booster fans and restrictions on the locations of ventilation regulators are dealt with in a straightforward manner. This new approach is based on a common Operations Research algorithm for which there are many fast computer programs available.

Jan 1, 1982

By David J. Maguire, Ken Alexander, Maya Scherbakov

As conveyor systems continue to improve in reliability due to improved design, installation, maintenance, and operation, one of the more common modes of failure is the rubber carry cover being abraded away to the tension member. Various types of abrasion are discussed as well as current laboratory methods for measuring wear. New lab methods to mimic types of abrasion in service are presented and data from current and improved rubber covers will be presented. Actual wear performance of current and new cover compounds in multiple applications (coal, limestone, granite) will be compared to the new lab test methods and cost benefits shown.

Jan 1, 2002

By Cyril W. Draffin

Introduction Americans have long been proud of their ability to recognize a need, define it, and then develop workable solutions. The U.S. underground coal conversion (UCC) program is a good example. In 1974, the need to utilize coal resources that could not be mined was recognized, and Congress gave the Bureau of Mines $1.7 million to gain a better understanding of the UCC technology and its potential applications. Since 1977 when the U.S. Dept. of Energy (DOE) was formed, workable technologies have been tested, the market for underground coal conversion has been recognized, and extensive industrial interest has developed. Perspective The U.S. is blessed with extensive coal resources. Coal supplies about 19% of our national energy needs, yet recently promulgated environmental standards and increasing mining costs have limited direct coal use. UCC potentially can use coal that is economically or technically infeasible to mine because the coal is too thick, deep, dirty, high-ash, and wet; has an excessive angle of dip; or has unpredictable and poor overburden characteristics that make mining unsafe. Coal can be gasified underground or perhaps liquefied below the earth’s surface. Underground coal gasification (UCG) is the prime element of the underground coal conversion program. It enables coal to be converted to gas underground. UCC Coal Resource Recent data show a total U.S. coal resource base of about 6.4 trillion tons. Of this, 1.8 trillion tons might be accessed by UCC, including some minable coal. A commercial UCC process could quadruple roughly the 450 billion tons of U.S. coal reserves, which presently are recoverable by mining. The U.S. coal resources are divided into five sectors. The two most eastern sectors contain relatively thin, swelling bituminous coals that are difficult to gasify. Of the two, the bituminous coal in the Eastern Province is the most difficult because it is deeper than , in the Interior Province and the terrain is more rugged. The sector along the Rocky Mountains contains huge amounts of thick low-rank coals that are the most promising for early development by UCC. The coal has good continuity and the terrain is suitable. Low-rank coals such as subbituminous and lignite are highly reactive and tend to shrink and disaggregate when heated. Most of the coal in the Pacific

Jan 1, 1980

By Mustafa Kumral, Mehmet Balci

Strategic mine planning focuses on cutoff grade selection, capacity planning and block sequencing. Despite significant knowledge accumulated, potential value can be added to mineral sourcing by addressing various aspects. A case study on a metallic deposit with a lognormal grade distribution examines if grade/metal distribution influences cutoff grade selection. Six data sets with different shape and scale factors, but the same ore tonnage and metal quantity, are analyzed. Results indicate deposits with lower shape and scale factors are more sensitive to metal price and discount rate changes. The study also investigates the effect of economies of scale (EoS) on project value, focusing on the ratio of variable cost to total cost (capacity factor). Two regression analyses are conducted for optimal capacity planning and cutoff grade selection. The first shows capacity planning is highly sensitive to the EoS of mining and mineral-processing costs, with grade variability and metal distribution being negligible. In the second analysis, grade variability and EoS of mineral processing costs are vital for cutoff grade selection.

Sep 1, 2024

By E. Rigopoulos

Mining disturbs the environment, even when the ores or the minerals extracted are non-toxic. Silver & Baryte Ores Mining Co S.A (S&B) is committed to minimizing the environmental impacts of its mining activities, by implementing an integrated rehabilitation program wherever it operates. The paper discusses the principles for mining-disturbed land restoration activities on Milos Island for a successful outcome.

Jan 1, 2003

By John Mastoris, Kostis Dragasakis, Kostas Kouklidis, Shkurtë Gashi, Halil Berisha, Jenuz Bulica

Titan Group’s environmental policy and Sharrcem’s Corporate Social Responsibility (CSR) are the driving forces behind the development and implementation of a comprehensive Rehabilitation Plan at Dimce Quarry, which is the main raw material source for Sharrcem Cement Plant since the 1970’s, located in the municipality of Hani i Elezit in Kosovo. Based on an Environmental Impact Assessment Study and the approved Mining Plan and also on the principles prescribed in the Guidelines on Quarry Rehabilitation, released by the Cement Sustainability Initiative of the World Business Council for Sustainable Development (WBCSD-CSI), Sharrcem has adopted a quarry operation and rehabilitation process in line with the best practices in the mining and cement sector. This paper discusses the background for the development of the rehabilitation plan and the results of rehabilitation activities, as have been implemented over the last few years. The main objective of the progressive rehabilitation plan at Dimce Quarry is to restore the depleted pit and return it back to the original land owners for resettlement. To date approx. 3,4Ha of former mining area has been restored by backfilling and levelling of the depleted closed pit and returned back to owners, who have built their houses and turned it into a living area again. This Quarry has turned out to be a real composition and practical example of preserving and returning back the natural resources in a state compatible with the surrounding environment and with respect to the needs of the local stakeholders. The motivation for business to engage in rehabilitation activities in the first place lies in the belief that the development and implementation of a progressive and practical Quarry rehabilitation plan and restitution of the land will deliver significant environmental and social benefits that outweigh the long-term rehabilitation costs, while maintaining the company’s reputation.

Jan 1, 2017

A Mark IV surface force apparatus (SF A) was used to conduct direct force measurements in dodecylamine hydrogenchloride collector solution between mica surfaces at varying pHs. It has been found that the long-range hydrophobic forces reach a maximum at pH 9.5, which also corresponds to the maxima attained by the contact angle and flotation recovery of quartz. The charge densities are comparable on both mica and quartz surfaces (0.40-0.48 run2), making it possible to draw conclusions on the flotation of quartz from the direct force measurements conducted on mica. Therefore, it may be suggested that the maximum flotation recovery of quartz m the range of pH 8.0-10.3 may be attributed to the appearance of long-range hydrophobic force, which in turn can be related to the formation of a close-packed monolayer (or hemimicelle) in the presence of neutral amines formed as a result of hydrolysis.

Jan 1, 1996

By RENE GOMEZ, RAUL CASTRO

Estimation tools and models are now available to estimate fragmentation, but some variables have yet to be studied to understand their effect on the fragmentation process. One such variable whose mechanisms have yet to be studied is the residence time, which in block caving directly depends on the distance that fragments travel from their original position in the broken ore to the drawpoint. In this study, granular material fragmentation was characterized during its flow to understand its characteristics and mechanisms. The results show that the breakage of fragment singularities occurred mainly within medium and smaller sizes, increasing fine material during flow. Thus, the main fragmentation mechanism in experiments was identified as abrasion between rock fragments where fine material continuously increases as distance increases in spite of the high rock strength and the piston flow movement used. The results presented here can be applied to incorporate fragmentation during flow of large travel distance of ore such as in block caving.

By Immo H. Redeker

Tile Asheville Minerals Research Laboratory is a member of the Engineering Research Department of North Carolina State University. The Laboratory is engaged mainly in applied nonmetallic mineral processing research to assist the North Carolina mining industry. A few out of state projects are handled at times. The Laboratory helped to bring the flotation process to North Carolina feldspar, spodumene, mica and phosphate producers and maintains versatile batch and pilot plant facilities at Asheville. It is of interest that North Carolina has now one of the newest and largest flotation plants at Lee Creek where Texas Gulf Sulphur Company produces 10,000 tons of phosphate concentrate per day, and one of the smallest flotation plants at Pittsburgh Plate Glass Company's fiberglass plant in Shelby, North Carolina where $50,000 per year of platinum-rhodium metal is reclaimed from wasted fiberglass furnace refractories in a tiny flotation operation of pilot plant size. The conservation of mineral resources through improved processing methods has been the object of most of the Laboratory's projects. This work has been extremely interesting and rewarding in many instances. Or, the example of projects for Kings Mountain Mica Company it will be demonstrated how waste could be reduced step by step from 20 tons of waste per ton of product to LO tons of product per ton of waste by improved processing methods. Brick, high grade potash feldspar, and silica sand are now produced from formerly wasted materials. AL this time Laboratory work sponsored by three feldspar companies, the State of North Carolina, and the U. S. Bureau of Mines, is aimed at reducing the amounts of feldspar tailings in the Spruce Pine area. Mineral dressing techniques are applied to reclaim saleable mineral products such as feldspar, mica quartz, and to make more uniform material for possible ceramic and other applications. Processes to produce new products such as sand-lime brick, and lightweight foamed autoclaved calcium silicate building products will be tested.

Jan 1, 1969

By S. K. Sahoo, S. K. Sharma, A. Yadav, B. Behera, G. S. P. Singh

A field representative modeling of the gob behavior is critical for the understanding of the associated mechanics of strata behavior in longwall workings. The findings of theoretical models and laboratory tests on the simulated gob material have shown the strain hardening behavior of the gob material. The double-yield material model, which is a built-in constitutive model in FLAC3D, has significant potential to simulate the gob compaction process as it represents materials which undergo irreversible compaction in addition to shear yielding. Apart from this, several researchers have attempted using modified elastic model or applied nodal force in reaction to the strain in the gob area as per the well-known theoretical relations to meet this requirement. Although these models can simulate the mechanical response of the gob for subcritical and critical extraction widths, they do not apply to supercritical extraction width as the gob stress may exceed the in situ stress level in such cases. For overcoming these limitations, a standard approach has been developed and validated in this paper, which can be used for simulating the gob behavior in supercritical longwall workings as well. The complete study is divided into two stages wherein the laboratory scale compression test on the simulated gob material has been numerically replicated to develop preliminary confidence followed by a parametric study of the double-yield constitutive parameters for a rational estimation of their values in different conditions. The calibrated model has been used for verifying its results by plane strain modeling of two different longwall workings, using well-established empirical and analytical findings and field observations. The approach suggested in this study can be used for the efficient modeling of the gob behavior of longwall panels under varying geo-mining conditions without compromising the accuracy of the numerical model. The meticulously validated model can be helpful in rational estimation of stress redistributions around the gob area apart from load transfer on the barrier pillar.

By M. Yekeler

The critical surface tension of wetting values (Ye) of realgar (AsS), talc [Mg3si401o (OH) 2]' stibnite (Sb2S3), and sulfur (S) were determined by flotation in the absence of conventional flotation collectors as 38.7, 38.0, 35.5, and 30.0 dyne/cm, respectively. The surface tensions of flotation media were arranged by methanol. Separation of binary mixtures of these minerals was performed exploiting their Ye differences-which form the basis of the "ganuna flotation process". One step flotation test showed that sulfur floats preferentially from its mixtures with realgar and stibnite at recoveries of 73.6 and 70.7 % and grades of 81.7 and 91.2 %, respectively. The separation of stibnite from realgar gave a recovery of 4.1 % and a grade of 41.2 % for stibnite, indicate that a minimal Ye difference of 3.6±0.2 dyne/cm is essential for such separation when conventional flotation reagents are not used. This paper presents data and describes the approach employed in these separations.

Jan 1, 1994

By A. D. Hammond

"INTRODUCTION The recent drop in iron ore prices has claimed an unwitting casualty in vanadium. Vanadium is dominantly produced as a co-product of steel production. The recent shutdown at EVRAZ’s Mapochs steel-vanadium operations in South Africa has cut-off 10% of the world’s vanadium output. Earlier in February, 2015, Australia’s Atlantic Ltd. suspended operations at its Windimurra iron-vanadium complex after a fire caused severe damage at the plant. Since then, challenging market conditions has resulted in the permanent closure of this operation. This decoupling of vanadium production from integrated iron ore producers presents an opportunity for vanadium exploration companies to target single-product deposits. This trend is manifested in the increasing number of pure-play vanadium ventures around the world.The mine production of vanadium is dominated by three countries namely, China, South Africa and Russia, which collectively produce 98% of the world’s vanadium. While the use of vanadium as an alloy in the steel industry remains by far the largest application for this metal, growth in demand is expected to come from the renewable energy industry in the form of batteries for energy storage. This paper summarizes the current state of vanadium exploration, briefly describes the vanadium market and lists sources of future demand for the metal. TREND IN VANADIUM EXPLORATION The most active participants in the current vanadium exploration are pure-play vanadium ventures in Brazil, South Africa and Australia. These ventures are targeting deposits with higher vanadium grade than those typically mined in titaniferous magnetite operated by integrated steel-vanadium producers. The 10% shortfall in vanadium production resulting from the shutdown at EVRAZ’s Mapochs is expected to be partially compensated by Largo Resources’ Maracás Menchen vanadium operation located in the State of Bahia in Brazil, which commenced operation in August 2014 and is expected to reach design capacity of 11,400 tonnes of vanadium pentaoxide (V2O5) by the end of 2015. The estimated production1 for 2015 is 6,500 tonnes of V2O5 at a target production cost of $3.60/lb. This is the first vanadium operation to be placed in production in the Western Hemisphere in over 35 years."

Jan 1, 2016

By Deepak Malhotra

Is operator training necessary for optimization of flotation plants? The answer is obvious-Yes. The author suggests a three-phase program for operators when new plants are built or new crews are hired in existing operations. Case examples are discussed to illustrate the benefits of operator training.

Jan 1, 1999

By O. Olajide, E. H. Cho

A laboratory study of the jigging process with Pittsburgh seam coal has been conducted. The laboratory-scale Baum jig used in this study was a McNally-Norton LO30X Right Hand Model Baum jig with an effective screen area of 0.186 m2 Feed material was prepared by selecting a size range from 6 mesh to 1.91 cm. Solid feed rates were 27.2 kg/min and 32.7 kg/min. Water flow rates were varied from 37.9 to 94.6 L/min. It has been found that smaller particles give higher values of density of separation and lower efficiency of separation. Increasing water flow rate increases the discharge rate of clean coal at a constant solid feed rate. It appears that the efficiency of separation increases by increasing water flow rate up to a certain value, and then levels off upon increasing the flow rate further.

Jan 1, 1988