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By Marcus A. Wiley, Gregory Abramov

Borehole mining (BHM) is a remotely operated method of extracting rock material through boreholes by high-pressure water jets. Figure 1 illustrates a BHM tool and fluids circulation. The tool consists of at least two pipes, one for pumping down high-pressure water, the second for delivering slurry to the surface. This article reviews the BHM process. It discusses current and new applications for borehole mining and help the readers determine if BHM is applicable in their situations. Previous articles in ME about BHM explained either a particular project (ME, April 2001, pp. 33-36) or a newest patent in this area (ME, March 1991, pp. 313-318). However, neither one provided an overview on the modern BHM technology.

Jan 1, 2004

By C. Laughton

Construction of a Deep Underground Science and Engineering Laboratory(DUSEL) is proposed under the auspices of the US National Science Foundation(NSF). DUSEL will provide scientists and engineers with a research facility capable of supporting a broad spectrum of fundamental and applied research deep in the earth’s crust. Research partners are physicists, biologists and geoscientists. DUSEL research calls for the construction of a network of shafts, tunnels and caverns that will provide laboratory facilities at depths of up to approximately 2 kilometers. The Project is still in the planning stages but, the initial experimental program is taking shape and conceptual designs have already been developed at two hard rock mine sites. This paper discusses the overall program and key engineering tasks being developed to support the construction of deep, large-span caverns. These caverns will house a new generation of physics experiments. As currently scoped, the experiments call for the excavation of permanent caverns with spans of up to 60 meters, sited at depths in excess of a kilometer.

Jan 1, 2007

By F. Calizaya

The Western Mining Training and Translation Center is a consortium of four universities devoted to developing educational and training projects to reduce the incidence/accident rates in the mining industry. The center consists of Missouri University of Science and Technology, Montana Tech, the Colorado School of Mines and the University of Utah. It is fully funded by the National Institute for Occupational Safety and Health (NIOSH). The center manages 15 educational projects and one translation project. Hazard Identification and Risk Assessment (HIRA) for Small Mines is an educational project managed by the University of Utah. The objectives of this project are to identify critical mine hazards, assess risks; outline procedures to reduce accident/incident rates in small mines in the western United States and to train mine workers and super-visors on HIRA in each participating mine. To accomplish these objectives, the HIRA personnel visited 15 small mines in Utah, Colorado, Nevada and California. At these mines, most operators were employing independent contractors to perform several tasks ranging from drilling, blasting and mucking of rock at the work site to hauling ore to a processing plant. The operation of diesel-powered equipment was one of the major tasks performed by the contractors. This article presents three case studies in which contract workers performed a number of tasks with no reportable incidents but did so unsafely. It also highlights the training received by most contractors, the constraints imposed upon them and the safety hazards to which they are exposed most frequently.

Jan 1, 2008

By Lawrence M. Zanko

Eighteen coarse taconite tailings samples were collected in 2000-2001 from five western Mesabi Range taconite (iron ore) operations located in northern Minnesota, i.e., EVTAC, Hibbing Taconite (Hibtac), USX Minntac, Ispat Inland (Minorca), and National Steel Pellet Company (NSPC), to test their physical, geological, chemical, and mineralogical properties [Zanko, L.M., Niles, H.B., Oreskovich, J.A., 2003. Properties and aggregate potential of coarse taconite tailings from five Minnesota taconite operations, Minnesota Department of Transportation, Local Road Research Board, St. Paul, MN, Report No. 2004-06 (also as Natural Resources Research Institute technical report, NRRI/TR-2003/44)]. The goal was to assemble a body of technical data that could be used to better assess the potential of using a crushed taconite mining byproduct like coarse tailings for more widespread construction aggregate purposes, primarily in roads and high¬ways. An important part of the mineralogical assessment included X-ray diffraction (XRD) analyses and microscopic (polarized light microscopy, scanning electron microscopy, and transmission electron microscopy, i.e., PLM, SEM, and TEM, respectively) evaluation of the size and shape (morphological) characteristics of potentially respirable microscopic mineral particles and fragments. Quantitative mineralogy, based on XRD analyses, showed that the dominant mineral in all samples was quartz (55-60%), followed by much smaller amounts of iron oxides, carbonates, and silicates. Specialized microscopic analyses and testing performed by the RJ Lee Group, Monroeville, PA, on both pulverized (-200 mesh, or 0.075 mm) and as-is sample composites showed that no regulated asbestos minerals or amphibole minerals were detected in the western Mesabi Range samples. A small number (26) of non-asbestos and non¬amphibole mineral cleavage fragments/mineral fibers were detected by SEM out of 1000 fields analyzed, but most were identified as min¬nesotaite and talc, silicate minerals common to the Biwabik Iron Formation. Amphibole minerals, absent in coarse tailings samples from the five western Mesabi Range taconite operations, were present in a single eastern Biwabik Iron Formation sample collected in 2003 for Lake County from the Cliffs Northshore operation in Silver Bay, MN. Importantly, the Superfund Method for the Determination of Releasable Asbestos in Soils and Bulk Materials [United States Environ¬mental Protection Agency (USEPA), 1997. Superfund method for the determination of releasable asbestos in soils and bulk materials, EPA 540-R-97-028, U.S. Environmental Protection Agency, Washington], as modified by Berman and Kolk [Berman, D.W., Kolk, A.J., 2000. Modified elutriator method for the determination of asbestos in soils and bulk materials, Revision 1: Submitted to the U.S. Envi¬ronmental Protection Agency, Region 8, May 23, 2000] failed to generate any protocol fibers, i.e., fibers longer than 5 µm and thinner than 0.5 µm, from either the western coarse tailings samples or the single eastern Biwabik Iron Formation sample. The combined findings suggest coarse tailings and other taconite mining byproducts should be treated with the same common sense safety and industrial hygiene approach practiced for all mineral-based materials that have the potential to generate respirable dust. © 2007 Elsevier Inc. All rights reserved.

Jan 1, 2007

By Ray E. Harris

Introduction A resource of more than 122 Gt (134 billion st) of minable trona and mixed trona and halite underlies an area of about 3400 km2 (1300 sq miles) west of Green River, WY (Culbertson, in preparation) (Fig. 1). In 1982, the total domestic consumption of soda ash (refined trona) was 6 Mt (6.7 million st) (Kostick, 1983). About 90% of this came from Wyoming trona. This enormous deposit occurs in the Wilkins Peak Member of the Green River Formation that is of Eocene age. This formation is derived from sediments deposited in a large lake named Gosiute. Lake Gosiute occupied the Green River Basin in southwestern Wyoming some 38 to 54 million years ago. The Wilkins Peak Member represents a restricted, evaporite-rich cycle of deposition when the trona deposits were formed. A total of 42 trona beds are known. Of these, 25 are of sufficient thickness and extent to be considered minable (Culbertson, in preparation). The production of sodium compounds from the trona deposits in the Wilkins Peak Member began in 1896 when wells were drilled within the present boundaries of the town of Green River. The purpose of the drilling was for extraction of sodium carbonate brines. Sodium carbonate (sal soda) was removed from these brines at a plant in Green River. Bedded trona was discovered in 1938 in a core from an oil well drilled south of Westvaco. In 1947, the underground mining of trona began. Production has continued from 1948 to date. Currently, five companies are mining trona and producing soda ash from the Wilkins Peak Member in Wyoming. Additionally, Allied Chemical Co. mines and processes trona for Church and Dwight's sodium bicarbonate (baking soda) operation in Green River. Competition in the soda ash industry depends primarily on the efficiency of mining and refining, allowing for lower-cost production. Newer plants and mine designs should increase efficiency. Solution mining holds promise as an even lower-cost method of mining. Employment in the soda ash industry is declining since the newer mining and refining methods are less labor intensive. Declines in employment, however, may be offset as production increases. Due to the large resource, the availability of minable trona should not be a problem for perhaps hundreds of years. Geology of Wyoming trona deposits Forty-two beds of trona or mixed trona and halite occur in the

Jan 10, 1985

By A. K. Mukherjee

The roles of pulsating mechanisms such as the amplitude and frequency of the jig cycle are well established in jigging. Also well established are the roles of the size ratio and the volume fraction of the feed. In iron ore beneficiation plants, these process parameters are optimized to achieve the highest efficiency. However, the role of one of the more important feed characteristics, the liberation characteristic of the feed, has not been studied in detail. Evaluation of the liberation characteristics is difficult because the required washability test is not viable for iron ore feed. In this paper, a new method is proposed in which the liberation characteristics are measured through a separation efficiency value. In the new evaluation method, jigging parameters such as amplitude and frequency of the jig cycle are optimized from the fundamental understanding of the process dynamics and feed characteristics such as size distribution. Then, feeds with different liberation characteristics are tested to evaluate the liberation characteristics of feed in jigging.

Jan 1, 2008

Recent advances in GPS, machine guidance technology and telemetry allow an unprecedented level of control of surface mining operations. GPS technology can now locate the bucket of a shovel or the blade of a dozer within 50mm (2 inches).Some of the outcomes possible are: precise selective mining – even when the ore is visually indistinguishable from waste: tracking grade and tonnage of every ore parcel through the mine: real time productivity monitoring: detailed post accident safety analysis: tracking the movements of every piece of equipment. This paper will consider the contribution that GPS based machine control systems can make to ensuring that surface mining projects deliver the outcomes promised in the feasibility studies. Case studies of installations are presented.

Jan 1, 2004

By Hugo T. Dummett

I would like to share some observations about the mining business and place the ongoing discussion in the context of our changed world. The mining industry practices its trade in a universe defined by prices, laws and governments. Prices, as in what the industry is paid for what it produces, and the costs of goods and services. Laws that have to be transparent and fair. And governments that the industry prefers to be stable and supportive of the industry, and certainly not corrupt. However, the day-to-day realities of the mining business in 2000 are not what they were 10 years ago. Several events have occurred that have resulted in a less populated workplace that is obliged to work much smarter and faster. These include real declining prices for most mineral commodities; low and diminishing returns to company shareholders; massive restructuring of the industry through mergers, partnerships and alliances; gold’s changed role from reserve currency to just another commodity; the growing importance of native title and the startling imperatives of “sustainable development.” In addition, the “borderless world” now means that resource companies will need to pass the test of being responsible corporate guests who respect and enhance the social, moral and societal values of their host countries.

Jan 1, 2000

By Jonathan Baggett, Nino Ripepi, Amin Abbasi, Richard Bishop, Juan Monsalve, John Hole

This work focuses on the operational and safety issues associated with karst voids in large opening underground mines. Issues include water inrush, structural instability, and engineering uncertainty in these environments. Coupled with the fracturing prevalent in folded sedimentary rocks, karst voids are complex and challenging ground-control risks. Traditional methods of predicting karst void locations, such as probe drilling, are impeded by the inconsistent spatial distribution and variable sizes of the features as reported by Li et al. (J Rock Mechan Geotech Eng:232–242, 2010) and Hassan et al. (Procedia Chem 19:737–742, 2016). Ground-penetrating radar (GPR) is a geophysical technique that transmits radio waves into a medium and subsequently detects reflected waves via a receiver. The travel time and energy of received signals are then processed and interpreted. The difference in conductivity and dielectric permittivity between limestone and open karst cavities causes strong reflections. GPR is frequently used as a geophysical surveying technique in several industries; however, there is a lack of published research on underground mining GPR applications as reported by Zhao et al. (2015a; Geophys J Int:62–71, 2015b) and Eskelinen and Pellinen (Constr Build Mater:888–898, 2018). The purpose of this work is to demonstrate the use of GPR in an underground stone mine and to discuss the importance of karst void detection ahead of mining.

By R. L. Guerguerian

Nowadays, most grinding mills driven by a wrap-around ring motor are operating successfully. Some of the earlier problems could be attributed to the lateral stiffness and stability of their bearings. As a result, modifications to the bearings included the rearrangement of the shoes, or the addition of more shoes, closer to the horizontal centerline. This technical paper reports a study of the effects of bearings on the lateral stiffness of grinding mills driven by a wrap-around ring motor. The discussions cover the design of the four shoe trunnion bearings and examine the effects of the angular location of the shoes.

Jan 1, 2000

By John H. Gasper

The success of steep slope (>20°) contour mining depends on many factors. Most important is the selection of the mining method that best suits the premining site conditions environmentally and economically. These conditions can be divided into three categories: • Geometric conditions - machine limitations, slope stability restrictions, erosion capacity; • Physical conditions - material properties, rock strengths, ability to dig, driving surfaces; and • Chemical conditions - acid-base relationships, blending or selective placement of overburden. This article incorporates these conditions by conceptually modeling compliance-oriented contour mining methods, particularly haulback methods, using the combined front-end loader (FEL)/ truck, tractor/scraper, and FEL-truck and scraper. Engineering analyses, including machine selection, sequencing, ease of varying production rates, slope requirements (for stability and running surfaces) and drainage requirements can be performed after the geometric constraints dictated by in situ conditions and regulatory requirements have been conceptualized. Once all generalized geometries have been established, reduction to idealized, three-dimensional views is achieved. These are then reduced to two-dimensional symbolic models, mainly plan views but also elevations and sections. Equipment activities and operations are then conveniently overlayed. Without this simple, two-dimensional reduction, technology transfer remains awkward and non-analytical.

Jan 1, 1991

By George H. K. Schenck

In this decade of the 1.970's it is forecast that eight billion cubic yards of rock will be excavated from 400, 000 miles of new tunnels, drifts and other underground workings in the western world, according to estimates in a report of the Organization for Economic Cooperation and Development (OECD). It is expected that the cost of this work will be in excess of $54 billion in constant 1970 dollars. Most of this underground excavation will be in mining -- 97% of the tunnel length and 89% of the volume - -the balance in construction. In addition to this huge excavating task, in the 18 developed nations of OECD, will be projects in the Communist Bloc and in the developing nations. Underground excavation requires the successful completion of three principle activities: A. Break -- to free rock from the solid work face. B. Remove-- to clear the work area of broken rock. C. Support -- to assure stability of rock surrounding the underground excavation and to eliminate risk of rock collapse. In today's fully mechanized excavation systems, continuous miners, roadheaders or tunnel borers, (A) break the rock loose from the face, and (B) remove broken rock with their mucking devices and load it onto belt conveyors, mine cars, trucks, or any other appropriate haulage system for disposal. Such operations contrast to the more complex, intermittent systems employed when

Jan 1, 1974

By Siegmund Babendererde, Jan O. Babendererde

Extruded Concrete Lining combines technological and financial advantages. The tunnel lining is reliably embedded in the surrounding ground as the fluid concrete is extruded at constant pressure directly behind the TBM supporting the exposed surface. Ground deformation from the TBM passage can be compensated and the ground will be pre-stressed by the extrusion process. Developments in concrete technology permit high speed tunneling by use of a slip formwork attached to the TBM. Realised projects in Milano (Italy), Lyon (France), Frankfurt (Germany) and Akima (Japan) will be demonstrated.

Jan 1, 2001

By D. Brady

The need for onsite gas monitoring during, or following, a major incident at an underground coal mine has long been recognised. Recommendations from inquiries following Queensland mine disasters have included ?qualified persons and equipment for rapid analysis of gas samples be available in times of emergency? and that ?this may be accomplished by either mobile laboratories or laboratories established in each mining locality.? Following the Moura No. 2 disaster, the Queensland Government allocated funds to Simtars for a mobile laboratory to respond should such a disaster occur again in the future. This vehicle was commissioned in 1997 and has been used at many mine sites under a wide range of scenarios. Simtars, armed with over ten years of operational experience with this mobile laboratory, has taken an active role in the design and construction of a modernised replacement unit. With a twenty point tube bundle system and ultrafast gas chromatograph the result is, arguably, the best equipped mobile gas analysis laboratory for mine emergency response in the world. This paper outlines the features of the new laboratory, its capabilities and the philosophy behind the design and inclusions.

Jan 1, 2012

By Aijuan Zhang, Liang Zhao, Yutao Wang, Yu Bao

In the green backfilling mining of underground coal mines, gangue in a coal seam is used to replace and fill goafs. However, the gas drainage time changes in the amount of gangue output and order in the extraction sequence of stope blocks, thereby changing the production output. A multi-objective integer programming model was proposed to solve this based on an improved non-dominated sorting genetic algorithm. The results show a feasible gangue filling rate can be found and the extraction sequence for a long-term planning time is optimized. It increases the planned annual output by 26% and reduces equipment idle time.

May 23, 2022

By N. Loganathan, Tan Boon Tee, Joe O’Carroll, Richard Flanagan

In recent years, tunnelling activities in Singapore have increased considerably with the construction of extensions to the existing sub-surface transport system, a deep tunnel sewerage disposal system, and tunnels for the laying power cables and other utilities. These tunnels are excavated through urban areas, adjacent to high-rise buildings, depressed road structures, beneath other tunnels, and buried services. Earth pressure balance (EPB) tunnel boring machines (TBM) have been used extensively in Singapore with great success. The risk associated with soft ground tunnelling, including tunnelling through Old Alluvium, can be minimized with an understanding of the geology, geotechnical parameters, and the tunnelling-induced behaviour of Old Alluvium (OA The purpose of this paper is to present some design and construction aspects of EPB TBM tunnelling through Old Alluvium.

Jan 1, 2005

By Charles Merguerian

In medium- to high-grade metamorphic terrains such as found in New York City(NYC), rock mass texture and mineralogy are important factors in predicting TBM penetration destiny. Integration of data from over two decades of traditional field and tunnel mapping suggest that hard-rock TBM penetration in the NYC area depends upon textural, mineralogic, and structural control. The bedrock of NYC consists of many different lithologic units of varying age, composition, texture, and metamorphic grade including many varieties of intrusive rock. In addition, brittle faults of numerous orientations cut the polydeformed crystalline bedrock, producing zones of highly fractured and disturbed ground and high water inflows. Pre-bid compilation of published bedrock data, drill core analysis by geologists to establish lithologic and mineralogic trends, integrated surface geologic mapping along a proposed alignment, and targeted petrographic and geotechnical investigations to characterize the rock mass conditions together constitute an important prelude to successful subsurface bidding and tunneling. A carefully planned program of as-built geological mapping, structural analysis, fracture class mapping, and monitoring of machine performance data provide important information for adjusting to changed conditions. In complex terrains, a clear understanding of the structural geology of any proposed tunnel line is the simplest and most cost-effective method to mitigate losses encountered during TBM tunneling.

Jan 1, 2005

By A. Opara

The weathering of coal mine waste rock releases iron, calcium, sulfate and associated trace elements like selenium [Se], which are introduced to seepage waters. Nitrogen species, such as nitrate and ammonia, are also found in association with coal-mining drainages mainly due to leaching of residual blasting compounds. Elevated concentrations of Se are a ubiquitous occurrence in coal mining environments in British Columbia, with values ranging from below 50 to over 500 µg/L in site waters. Selenate is the most common form of selenium found in waste rock seepages, and is exceedingly mobile in aerobic freshwaters. A major concern with waterborne Se in British Columbia is the potential for its bioaccumulation in aquatic food chains. Treatment to remove Se from coal-mining wastewaters has proven to be challenging for conventional water treatment technologies. Compounding this challenge, many streams are characterized by high flows and low selenium concentrations. Conventional membrane and ion exchange treatments produce concentrated brine streams that are difficult to treat or require disposal. Conventional biotreatment systems use excess nutrients to provide the required electrons to compensate for inefficient and variable electron availability, as well as to adjust reactor chemistry. The Electro-Biochemical Reactor (EBR) technology provides electrons to the microbes directly at a low voltage potential (1-3 V), supplying a controllable and consistent supply of useable electrons to the system and microbes at low current. In this manner, the EBR technology overcomes the shortcomings found in conventional systems, as it reduces the required nutrient addition and provides a more controllable, efficient, economical, and robust biotreatment system than found in past generations of biological treatment systems. Additionally, the EBR process does not produce excess solids or biomass; therefore, solids management post-treatment is not required. Laboratory EBR bench-scale and on-site pilot-scale systems were used to treat five British Columbia coal mine wastewaters; influent Se concentrations ranged from 35 µg/L to 531 µg/L. Se treatment targets for the tested waters ranged from 5 to 10 µg/L. Mean Se concentrations in EBR effluents ranged from 0.5 µg/L to 1.4 µg/L, while reducing sulfate concentrations. The test data demonstrate that the EBR technology is an effective Se removal option for British Columbia?s coal-mining wastewaters.

Feb 23, 2014

By A. Opara

The weathering of coal mine waste rock releases iron, calcium, sulfate and associated trace elements like selenium [Se], which are introduced to seepage waters. Nitrogen species, such as nitrate and ammonia, are also found in association with coal-mining drainages mainly due to leaching of residual blasting compounds. Elevated concentrations of Se are a ubiquitous occurrence in coal mining environments in British Columbia, with values ranging from below 50 to over 500 µg/L in site waters. Selenate is the most common form of selenium found in waste rock seepages, and is exceedingly mobile in aerobic freshwaters. A major concern with waterborne Se in British Columbia is the potential for its bioaccumulation in aquatic food chains. Treatment to remove Se from coal-mining wastewaters has proven to be challenging for conventional water treatment technologies. Compounding this challenge, many streams are characterized by high flows and low selenium concentrations. Conventional membrane and ion exchange treatments produce concentrated brine streams that are difficult to treat or require disposal. Conventional biotreatment systems use excess nutrients to provide the required electrons to compensate for inefficient and variable electron availability, as well as to adjust reactor chemistry. The Electro-Biochemical Reactor (EBR) technology provides electrons to the microbes directly at a low voltage potential (1-3 V), supplying a controllable and consistent supply of useable electrons to the system and microbes at low current. In this manner, the EBR technology overcomes the shortcomings found in conventional systems, as it reduces the required nutrient addition and provides a more controllable, efficient, economical, and robust biotreatment system than found in past generations of biological treatment systems. Additionally, the EBR process does not produce excess solids or biomass; therefore, solids management post-treatment is not required. Laboratory EBR bench-scale and on-site pilot-scale systems were used to treat five British Columbia coal mine wastewaters; influent Se concentrations ranged from 35 µg/L to 531 µg/L. Se treatment targets for the tested waters ranged from 5 to 10 µg/L. Mean Se concentrations in EBR effluents ranged from 0.5 µg/L to 1.4 µg/L, while reducing sulfate concentrations. The test data demonstrate that the EBR technology is an effective Se removal option for British Columbia?s coal-mining wastewaters.

Feb 23, 2014

By Eric M. Hill, Daniel E. Walsh, Hsing K. Lin, John T. Hollow

The Fort Knox Mine is located in Alaska’s interior where the average ambient air temperatures range from -24°C in January to 16°C in July. The mill processes a free milling gold ore utilizing both a gravity recovery circuit and conventional cyanide leach/carbon-in-pulp circuits. Plant slurry temperature cycles seasonally and allows for a unique opportunity to measure the impact temperature has on gold leach kinetics, carbon adsorption efficiency and cyanide destruction reactions. Mathematical models have been developed to accurately predict actual mill performance. This paper describes the development of the models and presents data that allow for a better understanding of the impact of circuit operating temperature on process efficiencies.

Jan 1, 2005