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By E. E. Jones

The lignites of Arkansas, Louisiana and Texas are typically described as muitiseam deposits which contain quantities of day and sand in thin lenses or in admixture with the fuel itself. These materials are often included in the run-of-mine fuel and can have very adverse effects in the end use. Since May of 1982 the Dow Chemical Co. has operated a pilot plant for the beneficiation of lignites. This facility has successfully removed sand, clays and petrified wood from the lignite producing a fuel comparable to or better than the selectively harvested run-of-mine materials. The design, operation and results from this plant were presented by J. H. Everitt at the 1984 Coal Technology Conference.

Jan 1, 1986

By Omid Frough, Hossein Changani

Application of Tunnel Boring Machines (TBMs) is one of the main solutions to achieve a safe and high-performance method of construction in hard rock and soft ground tunneling. In order to adequately assess the progress and potential impacts of the tunneling operations with the TBM, it is required to record a series of data during the tunneling and process of the data to evaluate the TBM performance. Applying the right machine parameters during the excavation not only delivers an optimum penetration rate, but also prevents extra downtime due to over excavation or wear of cutting tools. In this paper, the effect of machine and operational parameters on TBM downtimes has been studied and supported with the real examples of TBM operation data.

Dec 1, 2022

By A. Konya

"INTRODUCTION Underground Mining and Construction projects face several challenges unique to the underground environment compared to the surface environment. The goals of an effective blasting program are the development of a blast pattern that minimizes cost, maximizes face advance, and provides the desired fragmentation and face profile. In addition to these , mines must consider the very real operational problems that occur such as drill deviation, ground vibration, and deadpressing or sympathetic detonation of explosives. These operation problems lead to increased costs and decreased production in the mine, hurting the bottom line. Combined with these problems, underground blasts can be difficult to monitor and evaluate due to tight spaces, dust during the blast obscuring video, and the need to evacuate the immediate area with no clear line of sight to observe performance. This creates an environment which most mines know that blasting can be improved in their underground operations, yet most are hesitant to change due to fears of the shot freezing, misfires occurring, and questions about how to achieve a proper design. The explosive companies and shot service providers also offer limited assistance or knowledge in the underground blasting realm, unlike with surface blasting, leaving many underground operations in the dark. It is for these reasons that most underground operations are operating decades behind the current technologies and incurring significant costs, both real and hidden, from there blasting operations. This paper discusses philosophical changes to designs that need to be made for effective design and modifications of underground blast patterns to prevent deadpressing and precompression of modern explosive products (Konya, Konya, & Worsey, Modern Blasting Method Selection, 2017). While numerous different methods of underground heading development exist, there are two types that are used in a majority of mines around the world, these are the burn cut and the V-cut. The burn cut is a parallel cut that has holes that go straight into the face and are primarily used in smaller opening (due to ability to pull deep rounds with smaller room widths) and metal mines (helps in ore dilution and greater fragmentation). The V-Cut is a cut that uses angled drilling towards the center of the face (in the traditional method) and is primarily used in underground aggregate operations due to its cheap cost but larger fragmentation sizes and greater throw of the muckpile. This paper will discuss these two forms of cuts specifically with the understanding that modifications to these can be applied to other parallel and angled underground heading techniques. BURN CUT The burn cut is one of the older forms of underground blasting, where a part of the blast (burn) of a shot is heavily loaded with additional empty (relief) holes with the goal of smashing (aka burn) and pushing/blowing all the material in the burn out to provide relief for subsequent blastholes. The relief holes in the burn cut provide a parallel relief for the holes that are firing to break too creating a second plane of relief, however these are extremely small and can cause many problems if a design is improper."

Jan 1, 2018

By D. M. Larsen

Since start-up in 1985 the Cannon Mine has produced and shipped a 170 g Au/tonne (5 oz Au/ton) flotation concentrate to various smelters for gold and silver recovery. Several processed have been investigated to economically produce dore' at the mine site from the refractory concentrate. This paper describes recent laboratory and pilot scale test work utilized in the process design and engineering feasibility study of a 73 tonne/day (80 ton/day) pressure oxidation and CIL facility. The designed pressure oxidation circuit utilizes a series of vertical autoclave units operating at 170°C (338"F) and 1.4 MPa (200 psig). Projected operating costs are discussed.

Jan 1, 1993

By Malcolm T. Wane

The subject matter of this paper, "Applied Rock Mechanics?," has its genesis in a recent field trip taken by the author. A more or less standard question asked at the mines visited was "How are you using the principles of Rock Mechanics to assist you in maintaining an efficient, safe, and competitive mining operation?" The question was couched in a number of different forms, but the intent was to determine whether or not a general theory based on reason and the scientific method was applied or whether the alternatives of tradition, intuition, ?common sense', revelation, ?shotgun methods' or authoritarianism were invoked. Perhaps two responses to this query will be illustrative of the general nature of the replies. At operation XYZ an extension to the known ore body has been found. The extension is of large enough size and grade that a mining scheme using load-haul-damp techniques is envisaged. Since this represents a departure from the present mining scheme, questions have arisen regarding pillar sizes, room and entry sizes and possible support requirements. A task force has been set up to expeditiously plan for these things and write the necessary specifications and requirements. The fundamental question was posed to members of this group.

Jan 1, 1971

By L. Yuan, J. H. Rowland III

"In 1995 and 2003, the Mine Safety Health Administration (MSHA) conducted surveys to determine the number of atmospheric monitoring systems (AMS) being used in underground coal mines in the United States. The survey reports showed data for the different AMS manufacturers, the different types of equipment monitored, and the different type of gas sensors and their locations. Since the last survey in 2003, MSHA has changed the regulation requirements for early fire detection along the belt haulage entries. As of December 31, 2009, point-type heat sensors were prohibited for use for an early fire detection system; instead carbon monoxide (CO) sensors are now required. This report will examine the number of AMS currently used in underground mines in the United States to see if there is a change in their use. The locations and parameters monitored by AMS are also discussed. INTRODUCTION The last survey conducted by the Mine Safety and Health Administration (MSHA) on atmospheric monitoring systems (AMS) used in underground coal mines in the United States (US) was in 2003 [1]. The survey report states that since 1995 there had been a steady increase in the use of AMS in underground coal mines as the technology of CO sensors was improved by manufacturers. AMS had become more reliable and some CO sensors could be purchased with the capability to discriminate between the CO produced from a fire versus CO produced from diesel equipment. This increase in reliability had reduced the number of false alarms and the response time. The faster response time to a developing fire allowed for the miners to take the necessary action to put out the fire or exit the mine. It should also be noted that at the time of last MSHA survey, some mines still used point-type heat sensors to detect the presence of a fire on conveyor belts. This detection method works by measuring the temperature of the air around the sensor. As a fire starts to develop, smoke and hot gases are produced from the combustion process, and the air is heated up. Once the air and gases reach a designated temperature detected by the point-type heat sensor, a fire alarm signal is generated. Studies have shown that the response times for detecting the presence of a fire using CO sensors are much shorter than using point-type heat sensors [2]. Finally, since the last MSHA survey, regulations have changed on the type of automatic fire detection systems permitted to be used in conveyor belt entries. As of December 31, 2009, point-type heat sensors are not permitted to be used for fire detection in underground coal mines in the US; instead CO sensors are required as a replacement (30 CFR 75.1103-4). This study will examine how the changing of the above regulations has impacted the use of CO sensors in underground coal mines in the US compared to their use based on the last MSHA survey. Importantly, in the previous MSHA survey, the data was recorded for producing and non-producing coal mines. In this study, only the data from the producing coal mines was recorded. Data was collected from a total of 235 coal mines for this study with the help of the MSHA district offices."

Jan 1, 2017

By Charles E. Robertson

As it becomes more and more apparent that our nation must place a great deal of reliance on coal as an energy source in the coming decades, prospecting for new reserves Un Missouri and other states in the Western Interior Region is increasing. As more and more of the known reserve becomes committed to existing or planned projects operators will be forced to look beyond the fringes of existing coal fields for additional reserves. Perplexing geologic problems invariably confront all prospectors and are particularly bothersome to those new to a particular area. It is the purpose of this paper to alert prospective operators to geologic problems likely to be encountered and to offer guidance in the recognition and solution of these problems. Particular emphasis is placed upon geologic structure and washouts. Other geologic problems have been discussed in a previous paper.

Jan 1, 1977

Modern coal cleaning technologies have allowed coal preparation facilities to become quite efficient at removing sulfur compounds, waste rock and low grade coals from run of mine coal. Up to 50% of the raw mined coal stream may end up as refuse, particularly when the coal originates from longwall mining operations, or is high in partings, rock and impurities. The refuse materials vary from coarse materials removed by physical screening to very fine materials removed by floatation and density separation processes. Coal refuse piles are also known by a variety of other names including "waste dumps", "gob piles" and "slate dumps". The potential hazards of improperly reclaimed refuse include contamination of surface and groundwaters by acidic leachates and runoff, erosion and sedimentation into nearby watersheds, spontaneous combustion, disturbance of topsoil borrow areas, and damage from landslides should large slope failures occur. Many of these problems have been particularly acute for abandoned refuse piles, and modern regulations attempt to minimize the environmental impact of coal refuse disposal operations.

Jan 1, 1993

By I. Martinez-Dominguez

In September 1992, mining in Mexico was opened again to foreign investment by President Salinas-de Gortari, after thirty years of "Mexicanization" of mining industry which limited foreign participation up to a 49 % (or 34 % in case of national reserves) on a Mexican mining corporation. During said period mining in Mexico was controlled by four or five big mining companies and besides mining production was focused mainly on silver, lead, zinc, copper and fluorspar. Suddenly in middle of a big crisis on Mexican mining industry due to low prices of minerals in the world and also in a period on which it seems that mining industry in the United States and Canada has been condemned to die for environmental reasons, it appears a new Mexican Mining Law to permit foreigners to participate in mining in Mexico' trough Mexican mining corporations that they may control up to 100 %

Jan 1, 1994

By Ronald D. Jacksha, Jason B. Coder

Wireless technologies are becoming vitally important for modern mining operations. Used for increasingly complex tasks — such as miner and asset tracking, proximity detection, teleremote and autonomous equipment operation, and environmental monitoring — the ability of wireless systems to perform their intended functions satisfactorily in the presence of other wireless systems (coexist) is critical not only to the successful operation of modern mines but also to the safety and health of mine workers. Concerns regarding the ability of wireless systems to coexist can often hinder the decisionmaking process for adopting technologically advanced wireless systems. However, with adequate knowledge of the concepts of coexistence and appropriate wireless system management, coexistence concerns do not need to be an impediment to the successful adoption of wireless systems. There are several common wireless coexistence-related fears that can inhibit adoption of wireless technology: fears that safety-related systems may not operate properly when needed, failures could disrupt production, and wireless systems may inherently require costly troubleshooting. Most of these fears can be alleviated through proactive activities.

Apr 1, 2026

By L. Lacerda

Shotcrete is widely accepted as an indispensable form of ground control around the world. Other Surface Support Liners such as mesh have been around as long as shotcrete while other Thin Support Liners (TSLs) have been introduced in recent decades. TSLs, however, have yet to replace shotcrete in many applications believed to be “perfect” for them. On the other hand, some recently introduced technologies may be on the brink of meeting most surface rock support requirements economically and safely. This paper will discuss rockfall statistics, small rockfall prevention and compare different surface support liners such as mesh, shotcrete and TSLs. Additionally, a shaft sinking TSL application example will be presented.

Jan 1, 2004

By Gennaro G. Ph. D Marino

In order to improve handling of subsidence damages the Illinois Mine Subsidence Insurance Fund supported the development of novel cost-effective methods of repair. The research in developing the repairs was directed towards the most common and costly damages that had been observed. As a result repair techniques were designed for structurally cracked foundations in the tension zone; structurally cracked foundations in the compression zone; and damaged or undamaged tilted foundations. When appropriate, the postulated methods would result in: 1. significant cost savings (over conventional procedures); 2. a structural capacity greater than when the foundation was untracked; and 3. an aesthetic appeal. All the postulated repair methodologies were laboratory and/or field tested. The paper will summarize the essentials of each technique developed and the test results.

Jan 1, 1986

By Robert T. Beckman

Education of inspection and operating personnel is essential to protection from radiation hazards in the mining industry. For over 10 years, MSHA has presented the only formal course on radiation measurements and control available to the mining community. Course objectives and content are described in this paper.

Jan 1, 1981

By John P. Fillion

This paper will present an overview of conveyor haulage systems. Technical and economic feasibility will be examined as conveyor haulage is applied to large western surface coal mines. Theoretical analysis and actual cases will be presented from NERCO Coal Corp. experiences in bringing this application to their Western mines.

Jan 1, 1989

By Janusz Cygankiewicz, Marian Branny, Józef Wactawik

The paper presents mathematical model of concealed fire. We consider a porous medium (goaf, coal fissures) through which air flows. The set of equations is constituted by transient, two dimensional mass, momentum and energy balance equations with sources describing oxygen loss and heat generation caused by coal oxidation. Paper presents several examples illustrating the phenomenon of spontaneous heating in goaf areas behind longwall faces.

Jan 1, 1997

By Gary PE Beerkircher

A brief history of banana screen development and evolution will be presented along with the operational advantages of the large banana screens available in the industry today. Applications of the large banana screens will be presented as well as the economic advantages that the use of large banana screens can offer to the Mining lndustry today. Banana screen installations in metal, non- metal and coal mining applications will be presented.

Jan 1, 1997

By Lynda T. Holden, Philip L. LeHoux

Barneys Canyon Mine is a 1.8 million t.p.y. gold heap leach operation near Salt Lake City, Utah. The gold recovery plant has been operating since September of 1989. Carbon elution is done at atmospheric pressure with a high temperature caustic solution. No cyanide is used in the process. Operating experience is discussed.

Jan 1, 1990

By John C. Balla

The Spar Lake deposit is located in northwestern Montana, approximately 27 km (17 miles) south of Troy, MT, under Mt. Vernon. The deposit is a stratiform, stratabound copper-silver deposit occurring in the Revett Formation of the Proterozoic Belt Supergroup. Distribution of known sandstone-type deposits in the Revett Formation is shown in Fig. 1.

Jan 1, 1991

By Thomas J. Lien

AMAX Coal Company has constructed the first commercial demonstration sub-bituminous coal dryer at its Belle Ayr Mine south of Gillette, Wyoming. This 215 ton per hour facility is projected to produce 165 tons per hour of dried coal at 10 percent moisture and 10,800 Btulpound (6,000 KCIkg). Approximately 43 tons per hour of water will be removed from the coal and seven tons per hour of coal burned as fuel.

Jan 1, 1989

By M. K. Quinn, R. D. Chaffins, A. W. Khair

This paper presents an analysis of the effects of topography on static and dynamic ground movements and severity of damage inflicted on surface structures. A typical site containing varying topographical features (i.e., mountains, hillsides, valleys, and flat bottom land) representing the northern Appalachin region was chosen for the study. Typical subsidence monitoring techniques were employed. Frequent measurements were made as the face advanced.

Jan 1, 1987