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By T. J. Morris

"From November 2014 through September 2016, Westmoreland’s Coal Valley Mine utilized a Marion 7450 electric walking dragline to extract 1.2 million tonnes of a vertically-dipping, 52-meter wide, fault-thickened seam, beneath a conventionally-excavated pit bottom. Mine planning and operational hurdles encountered throughout a kilometer of mined strike length included mitigating highwall instability in both hanging and footwall slopes, water management, and end-of-life machine reliability and maintenance. The most substantial challenge has been the depressed global coal market. However, the successful application of this mining method significantly aided the overall cost of production at the site. The valuable experience gained from this project will be extended to future mining areas where this technique can be similarly applied. INTRODUCTION Coal Valley Mine is located approximately 220 kilometers southwest of Edmonton, Alberta, Canada, in the foothills of the Rocky Mountains. Since commercial production began in 1978, more than 84 million clean tonnes of coal has been produced and sold domestically as well as exported overseas for power generation. While the existing processing plant has a nameplate capacity of 4 million tonnes per year, the site has operated at a 2 million tonne rate since 2015 due to depressed export markets. Westmoreland acquired the mine as part of its purchase of Sherritt Coal Operations in April 2014. The mine operates 24 hours a day, 7 days a week, with an IUOE workforce of 261. GEOLOGICAL SETTING The geology of the Yellowhead Tower mining area differs significantly from previous mining areas at Coal Valley. The Mynheer coal seam discussed herein consists of steeply dipping, highly-sheared, thrust-faulted, and heterogeneous coal pods. Deep set, southwest striking thrust faults were the likely mechanism for the podding and have resulted in overturned, rolled and highly sheared seams with zone thicknesses of up to 65 meters.The hanging wall is characterized by soft bentonitic mudstones and siltstones, overlain by massive competent sandstone. The footwall is defined by a hard volcanic tuff, interbedded with thin, sporadic coal seams. The sandstone above and volcanic tuff below constrained the faulting system within this zone, enabling the mass podding that has afforded the opportunity for large-scale mining."

Jan 1, 2017

By J. A. Lepinski

The FASTMETSM Process is a coal-based process for converting iron oxide fines into metallic iron. The end product, direct reduced iron (DRI) is used as a low residual charge material in electric arc furnace steelmaking. This paper describes the FASTMET Process and its potential application in the United States. Operating results from a 175 kg/h process simulator are presented. Characteristics of the end product are discussed. Process economics are reviewed along with plans for scaling-up the process to full commercial size.

Jan 1, 1993

By Richard J. Frechette

Final reclamation of mine tailings impoundments typically involves addressing the broad issues of surface stabilization and water management. Surface stabilization includes immobilizing the tailings particles and providing long-term protection of the containment facility. Water management typically includes provisions for handling both the external water (rainfall and runoff) and the internal water (pore fluids). Wet tailings disposal facilities, and sites with limited access and steep topography, present challenges to implementing effective surface stabilization and water management plans. This paper presents a generalized discussion of the approach to tailings impoundment reclamation based on project experience.

Jan 1, 1995

By James W. White

From Modular's first truck-dispatching system for Phelps Dodge Corporation in 1979 to today's alliance between Modular and Komatsu, Ltd., innovation has been Modular's main product. This paper describes the growth of a mining products supplier and the philosophy and decisions behind that growth.

Jan 1, 1998

By A. Bruynesteyn

Procedures are discussed to determine if a waste material can become acid producing when left exposed to the environment. When wastes proves to be acid producing, methods are described that can be used to determine the characteristics of the effluents produced from a commercial size waste dump, taking into consideration that large quantities of pollutants can accumulate inside a waste dump during dry periods. The length of such dry periods and the quantity of rainfall greatly affect effluent characteristics.

Jan 1, 1980

By E. A. Metz

It has been approximately four years since the International Agency for Research on Cancer (IARC) reclassified crystalline silica as a "group one" substance. Since then, crystalline silica has been considered a human carcinogen. Silicosis is a preventable disease, and several aggressive campaigns have been developed to increase awareness of silica-dust-related problems in the industrial environment. New analytical techniques are now being developed to determine quantitatively the amount of crystalline silica in materials. Yet, still much is to be learned about the surface properties of silica and the way in which the disease progresses into full-blown silicosis. This paper discusses the interaction of free radicals generated by the mineral particles and lung tissue. It is the cell injury and DNA damage that progresses to fibrogenesis. Freshly fractured surfaces of silica contain free radicals. These free radicals play an important role in the stimulation of the alveolar macrophage and the development of the inflammatory reactions leading to the fibrotic response caused by silica. Engineers, scientists and physicians need to discuss the mineralogy of silica and the technical issues concerning the development of silicosis.

Jan 1, 2000

By Ray Soper

Important progress has been made in developing the K-Process as an alternative to cyanide as a method of recovering gold from ores and other materials.

Jan 1, 1998

By S. S. Peng

In this paper, the precise definitions for a number of commonly used subsidence parameters are given. The subsidence parameters have been determined using an integrated approach for 110 subsidence cases collected in the major US coal fields. Attempts have been made to establish empirical formulae for the parameters. The results of this study indicate that some traditionally-held concepts should be changed.

Jan 1, 1995

By K. A. Perry, R. Q. Eades

The University of Kentucky conducted inerting tests and angle of ejection tests on three types of rock dust. A newly developed hydrophobic dust was compared against typical dry and wet dust applications. This new product is designed to alleviate respirable dust concerns for dry dusting and caking issues with wet dusting. Samples for both test types were prepared in a laboratory and subjected to temperature and humidity cycles that are typical of an underground coal mine. Inerting tests were conducted in a 38-L chamber with a 5-kJ Sobbe igniter. Angle of ejection testing was conducted at the University of Kentucky Explosives Research Team’s laboratory in Georgetown, KY. The results of these tests indicate that the newly developed dust has improved results for flame suppression and ejection compared with typical wet dust applications. The significance of these results is discussed with regard to existing respirable dust regulations and the issues associated with caking.

Jan 1, 2016

By Thomas A. Morley

This paper deals with the minimization of ventilation costs for the controlled-flow mine ventilation network. Cost elements considered include the cost of power and the fixed cost of the fans. The problem is modeled in a mixed-integer programming format and solved via the branch and bound method. Computational experience with sample problems is discussed.

Jan 1, 1983

By C Rutter, N Shea, K Kolobe

The Henderson mine, a panel cave mine in Colorado, has undergone multiple ventilation system changes to meet dynamic airflow needs. This paper explains the ventilation designs for different production panels, the challenges faced, and the modifications made to optimize the ventilation systems. The study highlights the importance of a robust ventilation system for safe and productive mining.

Mar 2, 2022

By C. D. Litton, I. E. Perera

This report presents the results of experiments to evaluate different types of mine fire sensors in an underground mine environment using a commercially available atmospheric monitoring system. To determine how well carbon monoxide (CO) and smoke sensors respond for purposes of fire detection, experiments were conducted using test fires of different mine combustibles and for both flaming and nonflaming combustion. The experiments were designed to assess the response of fire sensors to different contaminants and different contaminant levels produced from the test fires. The experiments were performed in the Safety Research Coal Mine at the U.S. National Institute for Occupational Safety and Health’s Bruceton Research Facility in the presence of an average ventilating air velocity of 1.6 m/s (315 fpm). Five fire sensor stations were located downstream of the test fire at fixed locations, with each sensor station consisting of four sensors: a CO fire sensor and three different smoke sensors, of which two were evaluated by the Mine Safety and Health Administration (MSHA) for intrinsic safety and the third was used extensively in underground mines overseas but not evaluated by MSHA for intrinsic safety. All four sensors were mounted near the center of the entry and in the upper onethird of the entry height. A UL-listed combination ionization and photoelectric smoke sensor was mounted near the roof at the first sensor station and its responses were compared against the responses of the four CO and smoke fire sensors. Sensor response data, contaminant travel times, and the impact of fire on the existing ventilation flow are discussed as they apply to earlywarning fire detection. Of significance in the analysis is the need for performance standards for mine fire sensors in order to provide for consistent and timely early warning of developing fires.

Jan 1, 2014

By S. K. Nicol

Flotation, water-washing cyclones (hydrocyclones) and spiral concentrators are the three process units most commonly utilised in fine coal preparation. The results of testwork conducted on these three units will be presented and their performance and separation characteristics examined in detail. In particular, the dependence of the separation characteristics of each unit on particle size and the constraint this places on product quality (ash and sulphur levels) will be discussed. This dependence will be shown to be a critical criterion in the selection of fine coal circuits.

Jan 1, 1986

By T. A. Moss

The installation of equipment and structures at mines often requires the evaluation of unique loading and operating conditions. Consideration of these unusual features is required throughout design and construction and into operation. The necessity for employing sound civil, structural and mechanical engineering techniques to the design of structures and equipment is well understood. However, the influence of geotechnical factors on the overall behavior during construction and operation of these facilities is less appreciated. Mine operators routinely perform exploratory drilling for the purposes of defining ore deposits. These exploration activities can be extensive and often include provisions for assessment of subsurface conditions as they relate to the mining operation, i.e., requirements for ground support. All of these factors are important to the economics of the mine and are well justified. Surface facilities are provided to access and service the mine and they play an important role in the successful development and operation of a project. Headframes, hoist foundations and shaft collars, in particular, are examples of unique installations encountered at underground mine sites. The design and above surface behavior of these facilities can be analyzed with the usual fundamental engineering practices employed throughout the engineering professions. This requirement during the project development is understood and adopted. Unfortunately, near surface exploration for the purposes of assessing soil and rock conditions for foundations are often given a reduced priority and less consideration. This paper is aimed at providing an outline into the benefits and importance of performing such explorations and to provide a brief discussion of the merits of such an approach. References in the paper relate particularly to shaft headframes, hoists and shaft collars but the issues raised apply equally well to other installations of a similar nature, e.g. milling equipment.

Jan 1, 1992

By S. Kesler

Rössing Uranium Limited has operated since 1976 a large open pit uranium mine and extraction plant at a remote site in the Namib desert, South West Africa/Namibia. The geology (Berning, I., et al. Economy Geology) and the technical aspects concerning mining, grade control and metallurgy have previously been described (Rössing Uranium, Mining Magazin and Whyllie, R.J.M. "Rössing Uranium reaches rated production", World Mining). The improvement of leach 'extraction has been reported in 1984 (Kesler, S.B. et. al. "Uranium extraction at Rössing") and the installation of a central process control system has been described (Kesler, S.B. et al. "The introduction of a central process system at Rössing"). At the beginning of 1983 a decision was made to develop a computer system for metallurgical plant optimisation which included mass and volumetric balances, analytical assays for up to 5 chemical elements and the costs for the major consumables. Within 10 months this computer system was developed and implemented. A large number of test runs were made and computer studies were undertaken. The metallurgical division now has a scientific tool for production; planning for actual comparison with plant results and for strategic investigations and decision making.

Jan 1, 1986

By A. J. Getz

Major precious metals projects are underway in Australia, Papua New Guinea, Indonesia, the Philippines and New Zealand. This article reviews the status of those projects. Included in this review are project location, reserves, method of resource exploitation, anticipated production, and other unique conditions. The article is limited to major precious metals projects in the Western Pacific region. This is not meant to negate the attractiveness or importance of the many other projects in that area. The geographical setting of these five countries are shown in [Fig. 1]. The gold output of the countries has increased dramatically during the 1980s. [Table 1] compares 1980 and 1988 production figures. The compound growth rate is 120%. That reflects the attractiveness of the region’s resource base as well as the impact of price increases, new exploration models and processing technologies, and changes in government policies. If the 10 projects discussed here are all brought onstream, their combined output - at about 130 t (4.17 million oz) - would amount to an increase of greater than 50% over 1988 production from this region. Table 2 shows indicative production levels for each of the 10 projects. Dollar amounts are in US currency unless otherwise specified. Australian dollars have been converted to US dollars at the rate of 1.28: 1.00.

Jan 1, 1990

By H. E. Rowen

I hope my title is not confusing; even more so that I am not. Actually pelletizing and sintering, meaning both the formation of pellets and the hardening of them, are closely related to each other and to phenomena of nature. Figure. 1 This many-celled porous structure, frozen as it was at the fusion temperature and was being frothed by fast-moving gases, may be considered a typical piece of sinter. The same structures have been found in natural ores.

Jan 1, 1962

By Victor J. Scaravilli, C. Richard Linamen

This paper presents a case history of Southwest Interceptor Contract No. 1, Cleveland, Ohio. It details some of the problems and solutions of handling and erecting precast concrete segments in a small bore soft ground tunnel. It also reviews how specific interpretations of contract requirements and contract administration effect production, performance and productivity.

Jan 1, 1987

By Rolf J. Wesely

Recent events in The Peoples Republic of China indicate that a major effort is underway to increase trade with the western world. Gold production contributes to China's ability to participate in international trade. Consequently, the Chinese government places a high priority on increasing gold production. Many of the operating gold mines in China contain refractory ores that to date have not been efficiently treated. Figure 1 illustrates the description and location of a few of China's major gold mines. China recognizes that the technology necessary to economically treat this ore has been developed in the United States and other western countries. The country has therefore begun to seek assistance in evaluating several potential projects. Organizational structure Gold mining and processing in China is directed by the China National Gold Corp. (CNGC), headquartered in Beijing. The agency has a director in each province who is responsible for exploration, mining and processing. CNGC uses the services of two engineering organizations for metallurgical testing, process development and design engineering for their projects. The largest engineering organization is the Central Engineering and Research Institute for Non-Ferrous Metallurgical Industries (ENFI), also located in Beijing. The second engineering organization is the Changchun Gold Design Institute (CGDI), located in Changchun Jilin province.

Jan 1, 1993

By R. W. Barbaro

The limitation of sulfur dioxide in power plant emissions dictates that sulfur in coal be reduced to the lowest possible level before combustion so as not to aggravate the emission control problem at the stack. For coal fired power plants, the methods in practice to achieve low sulfur coal include mining areas with relatively low sulfur. reducing sulfur in the mined coal through preparation techniques and blending high and low sulfur coals. A prerequisite to the successful implementation of any of these practices is the knowledge of the spatial distribution and the capability to predict sulfur values in a coal seam.

Jan 1, 1988