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By Robert A. Jankowski, J. Harrison Daniel, Fred N. Kissell

Introduction Longwall coal mining in the US has steadily increased since its introduction in 1960. There are now 108 systems operating. (Sprouls, 1986). Advantages of longwall mining include higher productivity, improved safety, and greater coal recovery. Respirable dust, however, is one of the more serious obstacles to realizing the full potential of longwall mining. Early in 1980, the US Bureau of Mines (USBM) initiated extensive in-house and contract research to identify and evaluate effective methods of controlling respirable dust exposure of longwall face personnel (Niewiadomski, Jankowski, and Kissell, 1981). It was found that several control procedures must be combined to assure compliance, using control techniques appropriate to the dust source. These techniques can typically be grouped into the following categories: reduction of dust generation; dilution of dust; capture or knockdown of dust; and dust avoidance. Control techniques can be divided into basic and effective dust control techniques; additional necessary controls; and optional supplementary controls. This information should allow longwall mine operators to select control methods applicable to their particular operations and to develop a dust control plan that meets Federal dust standards. Basic and effective dust control techniques There are three basic dust control techniques (Taylor and Jankowski, 1982) that should be implemented on all longwall mining operations. • A passive barrier or external water spray system design that confines shearer generated dust near the face and away from the operators. • Large quantities of water through the sprays, particularly the drum sprays, to aid in dust knockdown and prevent dust becoming airborne. • A cutting sequence that allows the shearer operators to work primarily on the intake-air side of the lead cutting drum. Shearer clearer There are some poorly designed shearer-mounted spray systems with nozzles directed upwind at the cutting and loading zone of the intake-side drum. These actually carry dust away from the face and upstream of the drum. Where, it mixes with the clean intake air (Fig. la,) and is carried out into the walkway over the shearer operators. The Bureau developed a novel shearer spray system, called the shearer clearer. It takes advantage of the air-moving capabili-

Jan 10, 1986

By J. Kern, M. Cain, T. Torries

Until recently, the generation of electricity was regulated in all states and the value of generation assets in a regulatory environment for ad valorem taxation were based largely on the book value of the plant plus the rate of return on capital allowed by the state regulatory agency. This method of appraising utility generation assets is inappropriate in a competitive environment because past capital expenditures are not relevant in a competitive environment. However, it is not clear what valuation methods are appropriate after restructuring. This paper identifies key problems and advantages of other appraisal methodologies and makes comments on various valuation and taxation methods.

Jan 1, 2001

When overburden depth exceeds economical recovery in openpit coal mines, the use of highwall mining systems has increasingly come into play. However, stability in the highwalls is always a major safety concern during such mining. The U.S. Mine Safety and Health Administration requires that highwall mining operators follow ground control plans that specify the pillar sizes necessary to prevent collapse that would threaten highwall stability.

Jan 1, 2006

By Jan L. Reichelderfer, Thomas L. Richardson

Completion of the H-3 Highway Tunnel Project was a critical element in opening this award winning project. The exploratory tunnel was completed as a maintenance tunnel and included difficult shafts extending into the main tunnel cross passages. The project also involved a major addition to the traffic operations center including a deep excavation in close proximity to the tunnel portal structures. The projects also included various completions and improvements to the main tunnels, such as paving, drainage, maintenance, and a variety of critical life-safety issues, such as radio systems, telephones, etc. The highway opened in December 1997.

Jan 1, 2001

By A. Rai

"This paper provides an overview of the current use of auxiliary ventilation product and the challenges with limited air quantity in dead-end entry or working face. The PVC low frictional factor, low physical constraint and minimum leakage ventilation duct was development with ""made in US and used in US"". The PVC duct development covering operational and total cost of ownership with on-going success will be presented. This paper will discuss mine sites using new PVC vent duct underground and the results from operational and technical side making a difference. INTRODUCTION The Turquoise Ridge Joint Venture (TRJV) is located in northern central Nevada, and is situated within the Basin and Range province, near the northeast end of the Osgood Mountains (see Figure 1). The TRJV mine consists of typical Carlin type- gold mineralization characterized by low strength rock of altered limestone’s, siltstones, and mudstones. The weak nature of the ground facilitates the underhand cut and fill mining methods [3].Mining Method; Underhand cut and fill : The mine uses underhand cut and fill method which has 12’x12’ top cuts and several different size undercuts. The ore body is accessed off of a secondary development heading, utilizing a heading with a cross section of 14W x 14H or 15W x 16H configuration. In the wider and more massive zones, two headings in a production panel may be worked at any one time. Drift round lengths are determined by the type of drilling machine being used. An example of a typical topcut and associated undercut layout is shown in Figure 2. SECONDARY / AUXILIARY VENTILATION IN UNUNDERGROUND METAL MINES The auxiliary ventilation system provides the required air volumes at the face of dead-end developments and production workings, which in many cases may be considered as the primary method of assuring that the air quantity and quality standards in these working areas are satisfied. The Auxiliary fans and ducting systems are usually the primary means of delivering the required air volumes to the face of dead-end developments and production workings. Both centrifugal and axial-flow fans are used in underground auxiliary ventilation systems, usually electric powered. The internally direct driven axial-flow fans tend to be more popular because of their compactness and adaptability to staging. The most commonly used materials for ridged tubing are coated steel, alloyed steel, fiberglass and resin. Flexible (collapsible) ventilation tubing is also used and is usually made from neoprene-coated or nylon material. To add stiffness and reduce collapsibility these fabric ducts can be formed over a steel spring frame. A very important factor in the design of an auxiliary ventilation system is to minimize leakage and reduce the frictional pressure losses along the auxiliary ducting systems by minimizing their friction factors (K)."

Jan 1, 2015

By W. J. Mahoney

A good quality assurance program at a coal mine or power plant is accurate, timely and consistent. The quality analysis is accurate due to a complete sampling of the coal stream loaded into the unit train. The sample analysis is accurate because standardized testing procedures are applied. Once an analysis is completed, the results must be communicated to the electric utility in a timely manner. The electric utility needs the results to better manage the coal inventory at its power plants. A quality assurance program can also help a mine deliver a consistent product to a utility's power plants. The importance of accuracy, timeliness and consistency are based on major changes that are taking place in the electric utility industry.

Jan 1, 1994

By D. He

In China, the total reserves of vanadium, reported as V2O5, in stone coal is 118 Mt (130 million st). Recovering vanadium from such a large resource is very important to China?s vanadium industry. The technology now being used to recover vanadium from stone coal has the following two problems in the leaching process: a low recovery of vanadium and high acid consumption. To resolve these problems, a new leaching technology is proposed. The effects of factors such as H2SO4 concentration, liquid-solid ratio, temperature and time, and the types and additions of additives were studied. By adding 1.5% (by weight) CaF2 and leaching the roasted residue of stone coal with 5.4% (by weight) sulfuric acid at 90°C for 12 hours at a liquid-solid ratio of 2 mL/g, the leaching degree of vanadium reached 83.10%. This proposed leaching technology gives a feasible alternative for the processing of roasting residue of stone coal and can be applied in the comprehensive utilization of stone coal ores in China.

Jan 1, 2008

By F. Djahanguiri

The U.S. Bureau of Mines is conducting research on underground stope leaching of metalliferous ores to minimize the environmental impact of ore processing on the surface and to maximize minable reserves. An aspect of this research is to minimize pregnant solution losses and/or groundwater contamination by leach solutions. Bulkhead design and construction are important issues for solution control and stope leaching economics. A reinforced concrete bulkhead was designed, constructed, and tested for solution control in an underground mine near Idaho Springs, CO. This paper presents the bulkhead design methodology and construction procedure.

Jan 1, 1995

By G. Wozniak, R. Rostanski, H. Pfanz, G. Aschan, E. Sierka

"Industrial wasteland is a typical element of the landscape of all the industrialised regions in Europe. There are many examples from Poland as well as from other European countries that post-industrial sites have been undergone natural colonisation and succession to establish in some cases ecosystems of greater biological diversity than the original ecosystems. The post-industry sites regardless of any reclamation carried out, undergo natural successional processes. The respective biological diversity (number of species, and number of plant assemblages) reflects the micro-variety of the specific habitat. This paper summarizes the results of investigations, which have been carried out since 1989 on coal mine water sedimentation pools in the Upper Silesia Industry Region. The aim of this study is to demonstrate the diversity of spontaneous plant communities recorded on post-industrial waste sites. In the course of the long time fieldwork, plant assemblages representing nine phytosociological groups have been identified."

Jan 1, 2005

By W. M. Hart

The current Automatic Data Acquisition system developed by some support manufacturers makes it possible to continuously monitor and record changes in leg pressure and advancing ram stroke in every shield, and shearer position at any moment during the mining operation. In order to effectively use the massive data obtained from this system for improving production and maintenance managements as well as providing better roof control at a longwall face, the research currently conducted jointly by West Virginia University and Cyprus-Amax Coal Co. attempts to develop a Longwall Management System for mine operators. The LMS software package runs on a MS Windows NT environment and consists of four sub-systems: (1) Data Interpretation and Analysis; (2) Production Management; (3) Maintenance Management; and (4) Ground Control. This paper presents the details of each sub-system.

Jan 1, 1995

By Albert Adu-Acheampong

Fairmount Mineral's Maiden Rock underground sand mine historically delivered air to ventilate diesel-powered equipment at its working faces through high-resistance, 381-mm- (15-in.-) diameter PVC distribution lines. In support of plans for expanded production, three new, low-resistance ventilation design alternatives were analyzed. The study determined that adequate ventilation for expanded production was possible with various commercially available, high-volume/ low-pressure fans combined with a systematic layout of control structures. The recommended redesign was implemented in 2001, resulting in a significant increase in flow volumes and a noticeable improvement in the mine environment.

Jan 1, 2008

By Wern-ping (Nick) Chen

In concrete lined tunnels, formwork removal timing may be controversial. Contractors seek to strip the form as soon as possible, and designers seek to keep the formwork in place as long as practical to protect the fresh concrete. Formwork removal timing is normally specified as a function to its insitu concrete strength. This approach may work for smaller diameter tunnels, but fallacy occurs when applying this approach to larger diameter tunnels, since a larger diameter would experience more displacement than a smaller diameter tunnel from its own weight. Excessive deformation may fail a tunnel to meet its roundness criterion and overstress the lining causing cracking or falling from the crown. This paper presents a contractual mechanism to mitigate this issue.

Jan 1, 2008

By P. Lopez, E. Wellman, N. Risso, A. Anani

Current machine learning models used for roof fall hazard prediction are mounted on expensive sensors, computationally expensive, or lack the robustness for accurate prediction in the underground mining environment. This research aims to provide a design methodology for a robust, low-cost, deep learning-based algorithm for underground mine roof fall hazard prediction. A data sampling plan is developed to ensure the replicability and robustness of the developed model. In addition, feature engineering and transformation methods are described to identify relevant features for hazard identification. The methodology described here will be used in model development, tested, and implemented as a real-time mobile device application. The new tool will be expected to detect roof fall hazards in real-time and contribute to a crowdsourcing approach for underground hazard detection.

Feb 1, 2023

By R. L. Andrew

The southwest Pacific has produced at least four of the world’s premier porphyry copper-gold deposits, and the current level of exploration is likely to produce even more. An appreciable amount of gold is being produced with this copper, with obvious economic advantages. Gold content, in addition to their large size, makes the southwest Pacific’s porphyrycopper-gold deposits very attractive exploration targets. The recognition of telescoping and overprinting of porphyry systems has produced a greater awareness of the likely surface expressions, in particular the significance of advanced argillic lithocaps in porphyry exploration. The recognition of the spatial and genetic association of porphyry copper and epithermal gold systems (Sillitoe, 1972), as in other parts of the world, has had important implications for exploration in the Asia Pacific region.

Jan 1, 1995

German manufacturer DBT signed a contract to supply a sixth automated-plow long-wall system to Shenyang Coal in Liaoning province in northeastern China. This most recent order occurred just weeks after DBT signed a contract to deliver a fifth automated-plow longwall system to Datong Coal in Shanxi province. The plow will go into service at Shenyang Coal’s Hongyang Mine. Mining conditions at the mine, coupled with DBT’s advanced automated-plow technology, means that the system has the potential to become one of the world’s most productive thin-seam longwalls.

Jan 1, 2004

By Veerendra Singh, NILAMADHABA SAHU, ARIJIT BISWAS

Manganese (Mn) ferroalloys are chiefly consumed in the steelmaking process as a deoxidizing agent or as an alloying element to produce high-quality steels. These alloys are typically produced in a submerged arc furnace using coke, fluxes and manganese ores of a specific manganese/Fe (Mn/Fe) ratio. Preferred-grade manganese ores should have Mn content greater than 46 percent and Mn/Fe content greater than 5 to produce commercial-grade, high-carbon ferromanganese [1]. Selective mining of high-grade Mn resources has created a scarcity of these resources, which is emerging as a major challenge for the manganese and steel industry. Manganese ore resources are mainly distributed in South Africa, with about 32 percent; Ukraine, with about 17 percent; Australia, with about 17 percent; and Brazil, India, China, Gabon and Mexico, with lesser amounts.

By E. McCullough

"Fostering positive community relations is a principal tenet of sustainable development, but conflict can test even the strongest of relationships. While conflict surrounding resource development projects has the potential to be destructive, it may actually pose opportunities for partnership and collaboration when managed effectively. It is therefore not only important for mineral resource professionals to recognize the financial and social costs associated with legal disputes among project stakeholders, but also for them to prioritize resolving social conflict using alternative channels that allow for win-win outcomes. A variety of dispute prevention and resolution techniques do exist, but successful practice is not yet the norm. Here we review the sources and consequences of social conflict in the context of mining projects, and discuss typical and alternative approaches to conflict management in light of their respective benefits and drawbacks. We also suggest implementation of conflict resolution lessons into resource-related university curricula as a critical step in the continued shift of the mining industry towards sustainable development. INTRODUCTION Social conflict is a recurring phenomenon in the human experience and serves as a critical mechanism for change [1-5]. It occurs when two or more parties perceive that their needs and interests are in direct competition with each other and believe they cannot be reasonably accommodated. Conflict over mineral resource activities, particularly the distribution of benefit and risk, has become an omnipresent issue throughout the world [6-7]. Contrary to common perception, however, conflict can be a positive, transformative encounter in some instances [2, 8-11]. For this to be possible, society and its acting agents must reconsider how to address conflict. What if conflict were only a challenge to try something different? It is well-understood that the mineral industries must manage an increasingly significant volume of social conflict [12-13], which can be a costly externality impacting all of whom are involved. We commonly consider conflict in a two-party sense, but this deeply over-simplifies the true number of stakeholders. Besides mining companies and community members, government policymakers and regulators, public interest groups, and judicial systems, to name a few, bear the social expenses of poorly-managed conflict [4, 6, 12, 14-22]. It is desirable for interested parties to participate actively in a constructive way to pursue their needs rather than contributing to adversarial relationships, operational problems, and legal costs [1, 4, 12]. Some mining companies are of course already working to develop more productive relationships with their stakeholders, but there is undoubtedly still a gap between ideal and common practices. This gap can inhibit collaboration and threaten the potential for mutually-beneficial resolutions to complex social issues [12]."

Jan 1, 2016

By Ronald R. Rose

Currently six economic heavy mineral deposits are known on the Penholoway Terrace. These are (from south to north) the Green Cove Springs Mine (GCS), Boulogne Mine, Folkston Mine, Mission, Lulaton, and Ludowici. The GCS deposit is located to the west of Highway 17 between the towns of Green Cove Springs and Palatka in the state of Florida and has been mined since 1972. To the north, the erosion created by Black Creek restricts the northern extension of the orebodies and to the south a karst depression and erosion by the St. Johns River restrict southern extensions. The deposit is 20 miles long and up to 4.5 miles wide. Deposit thickness is from 5 feet up to 45 feet. The deposit is a series of regressive barrier island sequences deposited during the Pleistocene along the ancient Penholoway and Wicomico shorelines. The initial transgression of the ocean up to the location of the western Henry orebody was an extensive sea-level still stand as evidenced by the unit thickness and stacked transgressive regressive sequences. This period was followed by sporadic regressing seas and still stands, progressing eastward and stranding the sand bodies which make up the East Extended, TE, and East TE Ridge orebodies. The orebodies are underlain by predominantly non-mineralized fluvial sands and occasional back barrier lagoonal deposited clays. There is a predominance of wetlands on the southern extents of the zone as the surface elevations decrease due to a large karst depression.

Jan 1, 2005

Clean Diesels fuel-borne catalyst, Platinum Plus, helps improve fuel economy for all engines up to 10 percent while reducing particulate emissions by up to 25 percent. When used with a simple diesel oxidation catalyst, particulate emissions can be reduced by 30 to 50 percent. The use of Platinum Plus enhances combustion in the cylinder, burning fuel more completely. This reduces CO2 and other greenhouse gases and lowers total operating costs by improving fuel economy.

Jan 1, 2007

By W. G. Willson, D. E. Walsh, B. Irwin

Low-rank coal (LRC) drying processes are generally categorized by operating temperature, drying environment and type of feed (either sized or ground coal). Within these broad categories, drying processes differ according to the type of drying equipment and methods of quenching and stabilizing the dried products. This paper focuses on the produce quality of various LRC drying processes including conventional low and high temperature evaporative drying and non-evaporative, hydrothermal drying. The former may be preferred if the dried product can be utilized immediately, but moisture reabsorption, spontaneous heating and fines production during handling are problems associated with longer term storage, transportation and utilization. Methods for reducing these problems are discussed. Hydrothermal processing is an advanced technology featuring high pressure, non-evaporative drying, which solves stability problems by producing a liquid feel.

Feb 24, 1997