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By LaTasha R. Swanson, Jennica L. Bellanca

Proximity detection systems (PDSs) for mobile machines have the potential to decrease injuries and fatalities. Early adopters of the technology have identified some challenges, which present an opportunity to explore and improve the integration of mobile PDSs in underground coal mines. The current research study applied the task-technology fit framework to investigate the fit between mobile PDS technology and mining relative to health and safety, from the perspective of leaders at two coal mines. Quantitative results from the study show that mine leaders evaluated mobile PDS favorably for training and ease of use, system feedback, user authorization and experience, and less favorably for safety, compatibility, task completion, and reliability. Qualitative results reveal specific task, mine, and system characteristics that may have influenced leaders’ evaluations. The study includes considerations and suggestions for safe technology integration

By LaTasha R. Swanson, Jennica L. Bellanca

Proximity detection systems (PDSs) for mobile machines have the potential to decrease injuries and fatalities. Early adopters of the technology have identified some challenges, which present an opportunity to explore and improve the integration of mobile PDSs in underground coal mines. The current research study applied the task-technology fit framework to investigate the fit between mobile PDS technology and mining relative to health and safety, from the perspective of leaders at two coal mines. Quantitative results from the study show that mine leaders evaluated mobile PDS favorably for training and ease of use, system feedback, user authorization and experience, and less favorably for safety, compatibility, task completion, and reliability. Qualitative results reveal specific task, mine, and system characteristics that may have influenced leaders’ evaluations. The study includes considerations and suggestions for safe technology integration

By Reginald Dias

Mining equipment life may be extended through preventive maintenance and the proper application of quality lubricants. There are several practices mine operators should consider implementing to preserve their equipment. An exercise in review — Begin by reviewing original equipment manufacturer (OEM) recommendations regarding servicing and maintenance intervals for each part of the equipment, especially the engine. And the verdict is — If the manufacturer’s recommendations have been followed, good. If not, owners/operators should begin periodic service work on equipment, to help minimize equipment downtime and extend engine life.

Jan 1, 2004

By Y. Q. Zhang, S. S. Peng

Numerical modeling was used to design the pillars and bolting plan for a mine with weak roof and multi-seam stress condition. Previous mining experience, pillar/roof yielding and in-situ horizontal stress were considered in the models. By modeling the upper seam yielding and vertical stress transfer, a multi-seam influence zone was obtained. Appropriate pillar sizes were designed for conditions with and without upper seam stress influences. Roof support for the track and belt entries, using fully-grouted resin bolts and cable bolts, was proposed and implemented in the model. The bolting plan was evaluated under the weak roof condition.

Jan 1, 2004

By Adam Zanker

Smooth roll crushers are widely used as secondary crushers, operating most effectively when set for size reductions in a ratio between 3 or 4 to I. The feed supplied to these units varies from 13 to 102 mm in size and the product obtained ranges from 13 mm to about 20 mesh. Smooth roll crushers produce very few fines and absolutely no oversize. The diameter otfhe rolls varies with the clearance between them, feed size, and the coefficient of internal friction ofmaterial to be crushed, Detailed calculations of this relationship may be found in Unit operations of Chemical Engineering, (McCabe, W. L., and Smith, J. C., 1967, McGraw Hill, NY, Chapter 26, pg. 825). The geometrical arrangement of the roll crusher is shown on the accompanying sketch. A relatively simple relationship between the diameter of feed, the roll, and the gap between them is as follows:

Jan 6, 1980

By Mohammad Djavid

The one-pass tunneling pipe jacking method has often been the most schedule and cost efficient method for the pipe line installation. The main challenges in jacking pipes larger than 108 inches and for longer runs are: transportation and logistics, requiring high jacking forces, keeping line and grades, control of ground surface settlement, providing adequate external lubrication, and the potential of damaging the joints and pipe spigots. In recent years, 144" diameter pipes have been jacked for short runs of up to only 300 feet. In this article design and construction of installation of up to 1,000 linear feet run of 144-inch internal diameter, reinforced concrete pipes without intermediate jacking station in Chicago O?Hare International Airport are discussed. The article also presents discussions regarding the subsurface saturated silt formation, shallow cover, dewatering, jacking and receiving shafts, jacking forces, lubrication and settlement data.

Jan 1, 2008

By Yoginder P. Chugh

Most mines are large producing 0-25 mmt annually. The coal is mine.) at depths ranging from .0-150 m 120-500 ft mining at 300 m .(,1000 ft) depth is anticipated in the future. Single and multiple seams ranging from 3-12 m 10-40 ft) in thickness are mined. Most overburden is unconsolidated and consists of sands, and sandy or silty clays. The stripping ratio (volume of overburden to volume of coal mined) varies from 3-L. The overburden and coal is mined in benches 8-12 m -(24-40ft) high; the high-wall angle is about 45 degrees. Bucket wheel and bucket chain excavators are commonly utilized for overburden and coal removal, Some of the large overburden stripping machines nave capacities. Ranging from 4400-10,000 bank cu ( 6000-14,000 BC) per hour. The overburden from the upper benches is transported around the pit using the trains and belt conveyors. It is deposited in the spoils using large stacker-conveyor systems capable of handling 2550-7300 cu m/hour (7500-10,000 cu yds/hour). The overburden from the bottom two or three benches is transported across the pit using the conveyor bridges which are computer controlled. Conveyor bridges capable of handling overburden up to 60 m (200 ft) high are currently in use; a 60 a (20e ft) high conveyor bridge has a capacity of 85 x 10 cu ( 118 x 10 cu yd) annually. The coal is loaded in the trains directly and shipped to power plants or coke oven plants.

Jan 1, 1980

By A. Dale Wunderlich

Since Sept. 11, 2001, the author has been asked by several mining companies and mining publications to share some of his insights on how the terrorist attacks on the World Trade Center (WTC) and Pentagon might affect the mining industry globally. Until now, the author has been reluctant to express his thoughts in a publication that could possibly fall into the hands of terrorists and give them some ideas that they may not have been previously considering. However, the author discussed the contents of this article with several friends and acquaintances in the international intelligence community. They said that nothing commented on here is new to the terrorists. Potential terrorist targets Sources within the worldwide intelligence gathering community have told the author that current intelligence data indicates that it is likely that the Islamic fundamentalist groups responsible for the attacks on Sept. 11, 2001will likely be directing their effort at foreign business entities. Any overseas or any domestic businesses of highly visible companies that are part of the anti-terrorism alliance should consider themselves a potential target.

Jan 1, 2002

Diesel Particulate Matter (DPM) issues are very high profile currently in both Australian coal and metal mines and Australian states are generally moving to acknowledge and to broadly follow US 2008 final metal/non metal mine regulation limits of 0.2 mg/m3 submicron particulate matter, 0.16 mg/m3 total carbon particulate and 0.1 mg/m3 elemental carbon particulate. The real time DPM monitor is being developed on the base of the successful Personal Dust Monitor (PDM) unit. The objectives of recently completed Australian Coal Association Research Program (ACARP) study has been to finalize the design of a DPM unit, to undertake comprehensive and internationally recognized laboratory testing to evaluate the new design and to undertake an underground series of tests to establish the robustness and reliability of the new approach. Under the project Thermo Fisher Scientific has undertaken structural changes to the PDM to convert it to a DPM real time monitoring underground instrument, the D-PDM. The Pennsylvania Pittsburgh Research Laboratories of NIOSH (the group that originally contracted for the PDM development) has undertaken laboratory ?calibration or verification? testing. A phase of Australian mine robustness and engineering testing has been undertaken to ensure the instrument can effectively assist mine management to handle this health issue. Tests have been undertaken at points of expected high atmospheric DPM such as during Longwall face moves, Development RAM car, Eimco and PJB usages. The paper discusses how the monitors have performed within the underground mine environment in evaluating DPM during the various phases of the production cycle. They have closely examined the influence of aspects of the mine ventilation system. Results have been compared to alternative industry pollutant measuring approaches. The outcome of the project gives the industry access to an enhanced tool for understanding the mine atmosphere in the presence of DPM. Real time DPM monitoring will allow the industry to pin-point high exposure zones such as those encountered in coal longwall face moves where various vehicles work or in areas of constrained or difficult ventilation. Identifying of high DPM concentration zones allows efficient modification of work practices to reduce underground miners? exposure. Some outcomes of the ACARP project in this area will be discussed.

Jan 1, 2009

By Allan E. Koski

Ceveland-Cliffs uses a specialized software package in mine planning at the Empire Mine, an iron ore mine it manages on Michigan’s Marquette Iron Range. The application puts together years of mining experience that began in the early 1960s on the eastern end of the Marquette Range. The Empire Mine is in its 38th year of production. It uses the software to model a complex and highly variable low-grade magnetite ore body, capturing the economics of mining and processing to the final product. With special attention given to geostatistical methods, the software is used for all geologic modeling, ore reserve estimation, ore control, pit design and short- and long-range planning.

Jan 1, 2000

By Gary J. Fletcher

Mining and processing activities which are proposed on private land, state leases, or unpatented mining claims are governed by numerous local, state, and federal laws which identify the procedures and conditions which must be met before resources can be developed. The respective government agencies responsible for the administration and enforcement of these laws have promulgated supporting regulations and guidelines, and have implemented certain permit and approval processes to ensure compliance. Each exploration project has a unique environ- mental setting and location which further dictates the types of air, water, hazardous waste, and wildlife laws and regulations which must be complied with before development commences. The environmental planning process should be the first step in the evaluation of existing company properties and the potential acquisition of other mineral properties. However. many company don't consider the environmental requirements for a project until the decision is made to develop the property for mining and processing. If a mining company wants to expedite the environmental planning process, it must first develop an in-house process for evaluating the project and determining the environmental approval procedures in the state where the project is located. The first stage of environmental planning involves general information which can set the overall company philosophy for development of projects.

Jan 1, 1987

By Christopher J. Bise

PRINCIPLES OF MINE PLANNING During the initial planning stages, all mining operations are analyzed and evaluated in a similar fashion. This similarity holds true because the mine-planning procedure can be reduced to a network of interrelated systems that are tied together by a common philosophy of mine planning: namely, that the resource is to be extracted in a manner which is safe, efficient, and profitable. The success of the mining operation cannot be guaranteed unless each of these three requirements is met. Fig. 1 shows a flowchart for the initial planning of any mining operation. Notice that there is a preplanning stage that leads to the planning of four interrelated systems. The preplanning stage includes property exploration, estimation of production and manpower requirements, and the establishment of construction timetables. The four systems, evaluated after the pre-planning stage, are broken down into the following: (1) Excavation and handling system, (2) Strata control system, (3) Operating support system, and (4) Service support system. The Excavation and handling system includes the selection of all the equipment for the removal of the resource from its in-place deposit (e.g., draglines, continuous miners, rock drills, etc.) and for the transportation of the mined material from the face (e.g., belt conveyors, trucks, etc.). The Strata control system incorporates all those considerations which maintain the integrity of the roof, ribs, floor, and overburden both during and after the extraction phase; typical considerations in this area include pillar sizing, artificial support of the immediate roof in mine entries, and subsidence protection. The Operating support system contains the "necessary evils" of mine planning; the system consumes a large percentage of the mining engineer's planning time but does not contribute to the actual extraction of the resource. However, if proper attention is not paid to the various components of the system, such as ventilation, drainage, and power, then the mining operation will not perform to its capabilities. Finally, the Service support system is composed of those operations which keep the mine running efficiently; typical examples of these include maintenance and sup- ply. One important concept that Fig. 1 is designed to emphasize is that the four systems are interrelated; typically, a slight alteration of one can affect the performance of another. If these interrelationships are ignored, the effects on the system can be disastrous. The mine preplanning stage and the four subsequent system evaluations constitute the Analysis portion of the mine planning flowchart. After this portion of the study is completed, the overall projected operation can be evaluated by techniques such as financial analysis. This last step in the study is referred to as the Synthesis of the previously calculated parameters into an overall plan. Much has been written about the overall evaluation of mining properties, but, over the past thirty years, very little has been written about the analysis of mine- planning systems in a coordinated manner. Further, those texts which attempted this topic have failed to give sufficient examples for successful implementation, thus supporting the operating engineers' lament that it is easy to discuss theories but difficult to show applications. This text is intended to bridge this gap. Examples of the various stages of the analysis portion of the mine planning flowchart shown in Fig. 1 will be covered in this text, with the exception of the Service support system, since this system is oriented more toward day-to-day planning than long-term mine planning. INTERNATIONAL STANDARDIZATION The benefits that can be derived from an international standardization of the units used in mining engineering calculations are numerous. The interchange- ability of equipment parts and the ability to analyze and compare performance and design specifications on an equal basis are just two of the goals desired by both manufacturers and mine operators. Unfortunately, conversion to an international standard has not been rapidly achieved by engineers in the United States, due to their training under the English system. The Society of Mining Engineers of AIME has made the commitment for the adoption of the Systeme International d'Unites (SI) in all mining engineering calculations. Since many practicing mining engineers and students in undergraduate programs still find difficulty in relating to SI units, the calculations in this textbook will use the English system, with Table 1 available for conversion into SI units.

Jan 1, 1986

By Hongsheng He, Xiaofang Lv, Jianfeng Wang

This paper provided an overview of characteristics of limonite ores as well as their influence on sintering performance. Evaluation experiments focusing on basic characteristics, granulation characteristics, and high temperature sintering characteristics had been conducted by using two types of limonite ores, then the principles of high effective utilization technology of limonite ores were discussed, and the sintering pot tests were conducted. Limonite ores possessed low total iron content, high combined water content, high SiO2 content, large average particle size, low adhering particles proportion, high porosity, high water absorption rate, short water absorbing time, poor granulation ability, high melt formation ability, low melt fluidity ability, low melt penetration ability, high melt absorption ability, low bonding phase strength, and high forming ability of SFCA. By taking the technical measures of ore-proportioning optimization, increasing the proportion of burntlime and segmentation granulation, the usage of limonite ores could reach 50% in sintering.

Aug 27, 2021

By Kerry Lahti, Bryan Ulrich

On Feb. 11, 2005, more than 20 mining professionals gathered in Elko, NV for a day-long round-table discussion on heap leaching. Attendees included project managers, operators and environmental professionals. They represented 10 mining organizations. Knight Piésold sponsored the special event. Its seven representatives included three staff members from the company’s Elko Operation, and one each from its Denver, Cajamarca (Peru) and Vancouver offices. The roundtable format was chosen to allow people from the mining industry to share ideas and experiences in an open forum. Rather than presenting prepared talks, spontaneity was encouraged. This resulted in a lively and enjoyable discussion.

Jan 1, 2005

By Richard Kastner, Emilie Vanoudheusden, Fabrice Emeriault, Jacques Robert

INTRODUCTION The subway line B of Toulouse (France) has been realized with three different tunnel boring machines (TBM) techniques: Contracts 2 and 5 are excavated with earth-pressure balanced TBM, Contract 4 with a slurry shield TBM, and Contract 3 with a compressed-air TBM. The first three machines are around 7.7 m in diameter, while the last one is 5.3 m. Moreover, a small part of the line (50 m) has been excavated by a conventional method. The tunnels run through the Toulouse molasses, composed of hard sandy clay with pockets and lenses of dense sand. Geotechnical investigations have shown that in these formations, K0 is greater than 1, around 1.8 at a depth of 25 m (Serratrice,2005) and that geotechnical characteristics are homogenous on the whole layout (? =22 kN/m3, Su = 300 kPa, c' = 30 kPa, F' = 32°). The water table is found between 2 and4 m below ground level. As geology, stratigraphy and tunnel cover (between 10 and 20 m) are almost identical, a comparison of movements induced by the excavation by each of the four excavation techniques is possible. This paper presents the soil mass movement measures in the case of the conventional excavation method and in the case of TBM sections. It shows how tunneling parameters may explain the different surface movements observed during excavation. For the sake of simplicity, only the results of Contract 2 (earth pressure balanced TBM)will be presented. MONITORING Monitoring for the Conventional Method Section For the conventional method section (Vanoudheusden et al. 2005) the mass soil movements are measured with two inclinometers and one multi-point extensometer borehole with automatic data acquisition (Figure 1). The monitoring devices include

Jan 1, 2007

By C. L. Kosmoski

The mining industry faces many workplace hazards that are a threat to human health and safety. The Bureau of Labor Statistics has found that employees in coal mining are more likely to be killed or sustain an injury or illness than workers in private industry. These injuries are also likely to be more severe (Bureau of Labor Statistics, 2007). In recent years, coal mining injuries have attained national attention due to highly publicized disasters. Despite these threats to worker safety and health, the U.S. relies on the mining of coal to meet its need for electrical power, with42% of electricity in the U.S. generated through the burning of coal (U.S. Energy Information Administration, 2012b; United Mine Workers of America, n.d.). Furthermore, the production of coal continues to increase and reach record levels every year(National Mining Association, 2012; U.S. Energy Information Administration, 2012a). For this reason, the coal mining industry must continue to find ways to protect its workers while maintaining productivity. One potential approach to protecting workers while maintaining productivity is through improving the safety culture at coal mines. In order to achieve this culture, operators, employees, the inspectorate, etc. must share a fundamental commitment to safety as a value. This type of culture is known in other industries as a ?safety culture? and can be defined as the characteristics of the work environment, such as the norms, rules, and common understandings that influence facility personnel?s perceptions of the importance that the organization places on safety. Fundamental to improving safety culture within an organization is understanding the existing safety culture; improvements cannot be made without first elucidating areas that require improvement. This manuscript details the process undertaken by researchers at the National Institute for Occupational Safety and Health (NIOSH) Office of Mine Safety and Health Research (OMSHR) to assess the safety culture at five underground coal mines across the United States. The purpose of this manuscript is to introduce the mining industry to a multi-methodological approach to safety culture assessments. Further, it is the goal of this manuscript to highlight the value of including both quantitative and qualitative methods into safety culture assessments in order to obtain the most comprehensive view of an organization?s safety culture. Because this manuscript focuses solely on the methodology implemented, data and results obtained during the five safety culture assessments will not be presented in this manuscript, but will appear in a future publication.

Feb 27, 2013

By Murat Erdemoğlu, Turan Uysal, Thierno Saidou Barry, Mustafa Birinci

The rapid development of the global alumina and aluminum industry is straight coupled with the demands and the needs of these materials. Nowadays, the only well-known accessible resources to produce alumina and aluminum are bauxite ores. But bauxite ores are limited, and the remaining exploitable reserves do not have high contents in alumina. In countries where there is little or no bauxite reserves or where the recovery of existing bauxite ores to produce alumina with the Bayer process are not economic, alternative resources for alumina have been explored. The most attractive resources for replacing bauxites are aluminosilicate clay minerals and coal fly ash. The important processes developed for the recovery of alumina from these sources are acid leaching and alkaline leaching processes. The acid leaching is known as the most efficient in which thermal and mechanical activation are included for improving the performance of the process. The objective of this review is to give a comprehensive insight on the production of the alumina from thermally or mechanically activated clays and coal fly ash by hydrochloric, sulfuric, and nitric acid leaching processes.

By K. M. Mohamed, R. K. Zipf

The shear strength properties of generic cement foam material and cement foam/concrete interfaces were examined at three testing scales. In laboratory direct shear tests on specimens with average shearing area of 0.006 m2 (10 in.2), the cement foam material had average peak and residual shear strengths of 0.88 MPa (128 psi) and 0.39 MPa (56 psi), respectively. Depending on the concrete strength, the cement foam/concrete interfaces had peak and residual shear strengths ranging from 0.71 to 0.81 MPa (103 to 117 psi) and from 0.27 to 0.29 MPa (39 to 42 psi), respectively. In laboratory direct double shear tests on specimens with average shearing area of 0.084 m2 (130 in.2), the cement foam/concrete interfaces had average peak and residual shear strengths of 0.17 to 0.30 MPa (25 to 44 psi) and of 0.11 to 0.23 MPa (16 to 33 psi), respectively. In large shear tests of simulated cement foam seals with the Mine Roof Simulator (MRS) test frame, cement foam/concrete interfaces with shearing area of 1.486 m2 (2,304 in.2) had average shear strengths of about 0.08 and 0.16 MPa (11 and 23 psi) along the roof and floor interfaces, respectively. The average shear strength through the cement foam material was 0.38 MPa (55.3 psi). Finite element analysis of the large seal tests and the back analysis of the shear strength of full-scale cement foam seals conducted at the NIOSH Lake Lynn Laboratory confirmed shear strength of about 0.14 MPa (20 psi) along the seal/rock interfaces. The study concluded that the structural analysis of cement foam seals should be based on their residual shear strength determined from small laboratoryscale tests of the cement foam/concrete or rock interface and not be based on their peak strength.

Jan 1, 2014

By C. O. Brawner, J. Kalejta II

The classical approach to control rock fall and ravel in open pit mining has been to use catch benches. The width and volume of benches is most dependent on the bench height, size of loading equipment, blast damage to the face and mining regulations. This was compatible with open pit slopes of less than about 45°. As our understanding of rock mechanics and blasting control has improved over recent years, much steeper rock slopes can be developed at many open pit mines. However, narrower benches result with less rock fall capacity. The transportation industry has been very successful in using catch fences to protect highways throughout North America and Europe for years. The authors recommend that cable and ring net fences have a potential major application in open pit mining to allow steeper rock slopes with significant economic benefit. This paper outlines the application, design and operation of catch fences in surface mining for specific conditions. Typical case examples are presented.

Jan 1, 2002

By M. L. Mellish

The year 1988 unexpectedly turned out to be a good year for the US coal industry. In fact, it was a third consecutive year of record coal production. Accord¬ing to preliminary Energy Information Administration data for 1988, domestic coal consumption went up 5%, or 41 Mt (45 million st), from 1987. Coal exports were up by a surprising 13.6 Mt (15 million st). In 1988, 22.7 Mt (25 million st) of coal were drawn from stockpiles for consumption. Even so, US coal production increased to 862 Mt (950 million st). That was up 28 Mt (31 million st) from 1987. While coal consumption, exports, and production were up, delivered prices for steam coal continued to slide during the year. Metallurgical coal prices, however, firmed up and showed a moderate increase. This reflected tight metallurgical coal markets at home and abroad. Coal consumption US coal consumption reached 800 Mt (882 million st), compared with 759 Mt (837 million st) in 1987. Increased metallurgical coal consumption was one factor. Most of the rise in coal consumption, however, was due to unexpectedly high electricity demand. Unseasonably hot summer weather al lowed added coal-fired electric generation to supplement the drought-related reduction in hydro-electric power supply. Electric utilities consumed 687 Mt (757 million st) of coal in 1988, 35.4 Mt (39 million st) more than in 1987. Coal-fired power plants remained the primary source of US electricity generation, providing 57% of the total in 1988. Coal consumption at coke plants increased 13%, to 38 Mt (42 million st), from the level consumed in 1987. This increase reflects the recent recovery in the iron and steel industry. Metallurgical coal consumption in 1988 could have been greater. But US coke plants reportedly reached their maximum practical production capacity. As a result, net US coke imports amounted to 1.45 Mt (1.6 million st). Despite increased industrial activities, steam coal consumption by industrial plants was up only slightly from the 1987 level, amounting to 69 Mt (76 million st) in 1988. Residential and commercial coal consumption remained virtually unchanged at 6.4 Mt (7 million st). Coal exports and imports US coal exports rebounded in 1988, reaching 86 Mt (95 million st). It was the highest level of annual US coal exports since 1982, when they reached 96 Mt (106 million st). An unusual set of factors led to an opening for US coal exporters in 1988: • a high level of industrial production in Japan and the European Economic Community, • supply disruptions due to labor problems at coal mines in Poland and Australia, • a drought-related reduction in hydro-electric power generation in Canada, requiring increased coal-fired generation, • China's problems in meeting its export commitments, and • a fall in the value of the US dollar. US metallurgical coal exports in 1988 amounted to 56 Mt (62 million st), 9.1 Mt (10 million st) more than the 1987 level. Europe, Japan, and Canada were the principal importers of US metallurgical coal in 1988. European countries, in particu¬lar, increased their take by one-third of US metallurgical coal. The labor problems in Poland and Australia contributed to these higher levels of imports. So did increases in pig iron production of 8% in Japan and 9% in the European Economic Community. US steam coal exports - including bituminous, anthracite, and lignite-increase to 30 Mt (33 million st). This was up from 25.4 Mt (28 million st) in 1987 Contributing to this overall rise were 1.8-Mt (2-million st) increase in shipments to Canada and a 2.7-Mt (3-million st) increase to Europe. Unaffected by the somewhat tighter world coal market, US coal imports showed a slight increase to 1.8 Mt (million st) in 1988. Colombia continue to be the leading exporter to the United States, followed by Canada and Venezuela. Venezuela's entry into the US market is a relatively recent one, having made its first significant shipment in the fourth quarter of 1987.

Jan 1, 1989