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By Richard E. Gertsch

Mechanical mining holds great promise for the mining industry. Realizing this promise depends on developing the tools needed to mechanize a mining operation with a reasonable expectation of success. Mechanical mining entered the 1990s with new machines, new operating methods and new ideas for the future. Mechanical mining can provide higher production, increase safety, reduce roof support requirements, create smoother openings for better ventilation, substitute continuous production for cyclical drill-and-blast procedures, and create opportunities for automatic and teleoperated control. The full promise of this important technology still lies ahead. Obstacles include: • Long-term production prediction: Mechanical systems have a high capital cost. Although recouped by lower operating costs, the tradeoffs are not always clear to mine operators. • Cutting tools for hard rock: Rock of more than 103.4 MPa (15,000 psi) cannot be cut by flexible mining machines. • Machine designs: Many machines cannot convert the required power into rock cutting capability. • Engineering: Better use of the machines in the mine is needed.

Jan 1, 1994

By Brendan Demich, Brendan Macdonald, Timothy J. Orr, Jason Navoyski, Jennica L. Bellanca, William J. Helfrich

Recent advances in computing, rendering, and display technologies have generated increased accessibility for virtual reality (VR). VR allows the creation of dynamic, high-fidelity environments to simulate dangerous situations, test conditions, and visualize concepts. Consequently, numerous products have been developed, but many of these are limited in scope. Therefore, the National Institute for Occupational Safety and Health researchers developed a VR framework, called VR Mine, to rapidly create an underground mine for human data collection, simulation, visualization, and training. This paper describes the features of VR Mine using self-escape and proximity detection as case studies. Features include mine generation, simulated networks, proximity detection systems, and the integration and visualization of real-time ventilation models.

A glance at the following chart reveals that because of the continued poor economy, the slump in industrial mineral production continued into 1980. Gypsum was down 17% from 1979; cement down 9%, sand and gravel, 17%, and crushed stone, 11%. All these downward trends reflect the high interest rates and high costs that slowed construction starts. Domestic fluorspar was down 21% and imports off 14% due to the steel iudustry slump. However, potash production was up 8% and phosphate, 5%. Increased drilling activity spurred au increase in barite production of 25%. Most other industrial minerals posted losses with only a few insignificant increases. As expected, prices were higher, reflecting increases due to high costs for labor, supplies, and above all, energy. Increasing energy and transportation costs also had their effect on industrial mineral production. Railroad freight rates increased 16-22% including fuel surcharge; truck rates increased 11-14%a; and ocean freight rates increased 20% for finished goods. The 1979 shortage of boa and hopper cars did not continue into 1980-most likely due to low production of many of the hulk industrial mineral commodities. All in all, 1980 was not a good Year for industrial minerals.

Jan 5, 1981

By Christopher J. Bise

INTRODUCTION The transportation of men, supplies, and mined material from an underground operation is the connecting link between the mine plant and the surface plant. Unless the mine is accessed by a drift or adit, some form of hoisting system is necessary for slopes or shafts. This chapter will deal with the selection of wire ropes and hoists, two of the most important consider¬ations when designing a hoisting system for an under¬ground mine. WIRE ROPES General A wire rope is designed to transmit forces longitudi¬nally along its axis. Wire rope is used in a variety of mining applications because of its flexibility, high ten¬sile strength, and dependability. Shaft hoisting ropes and principal slope haulage ropes are usually custom-¬built; however, proper rope selection for slushers, car spotters, etc. should not be overlooked. Wire ropes for shafts and slopes, since they represent the life line for the mines, should be of the very highest quality improved plow steel. This quality is necessary to deal with the conditions of loading, winding, vibration, abrasion, and corrosion. Tables I and 2 display the specifications for the typical wire ropes used for mine haulage applications. The 6 x 19-class haulage rope is used for most hoisting where abrasion is not critical. On the other hand, where abrasion is critical, such as a slope application, 6 X 7-class haulage ropes are preferred. For other mining applications, manufactur¬ers' handbooks should be consulted. Selection The selection of a wire rope for a mining situation consists of simply applying appropriate safety factors to a calculated maximum rope pull and comparing the result to the listed breaking strength of the rope under consideration. Table 3 can be used for determin¬ing the minimum factors of safety for wire ropes. To determine the maximum rope pull, the following quantities must be known: the rope weight in pounds (x), the conveyance weight in pounds (y), and the weight in pounds of the load in the conveyance (z). These values are used to calculate the load due to gravity, the load due to conveyance friction, and the load due to rope friction. When these loads are added together, as shown in Eq. 1, the maximum (static) rope pull (RPS) can be derived:

Jan 1, 1986

By G. Gaidajis, K. Angelakoglou

The development of a tool for assessing the environmental sustainability of mining facilities is described in this study. The tool is based on the analysis of basic components of the examined system, i.e., the quantities of the incoming materials and outgoing wastes, their hazardousness and scarcity, the utilization of water and energy resources, and the biodiversity. The developed tool provides both qualitative and quantitative assessment of the environmental performance of a mining facility in a broad time scales (past-present-future) and is easily applicable from non environmental experts. Moreover, relative software is developed to further support the application of the methodology. The implementation of the tool is expected to lead to an improved understanding of the environmental performance of a mining facility and more importantly identify the areas of significant environmental concern. However, based on feedback from industries, a number of shortcomings of the approach have been identified so far and are presented, indicating further actions for the advancement of the proposed tool.

Jan 1, 2011

Komatsu America International has introduced two new hydraulic excavators. They can work in congested and confined areas. The tight tail swing radius of the PC128US-2 and PC22-8USLC-2 enables the excavators to minimize the work space. The units can operate in confined work settings that are inaccessible or counterproductive to traditional machines. Even the door is designed for tight working conditions. A convex door slides open along the exterior curve of the cab, rather than swinging out on hinges past tracks. And the excavators’ tight tail swing design allows them to load within the track width of the machine.

Jan 1, 2000

By T. L. Owen

Since 1993 Cyprus Amax has brought $2.5 billion dollars of greenfield and expansion projects into production, taking it from a mid-sized domestic minerals company into a major international minerals organization. The near simultaneous development of these multiple mineral projects in different locations around the world provided the opportunity for Cyprus Amax to develop a formal project management approach based, in large part, on an outsourcing philosophy. This formal project management system along with its outsourcing philosophy has served the growth agenda of Cyprus Amax extremely well. These preceding factors, coupled with the in-house retention of a core project group that fully understands the breadth of skills and abilities needed to undertake development of multiple large projects successfully, have been the cornerstone of Cyprus Amax’s project development success.

Jan 1, 2000

By N. I. Aziz, I. Tague, P. Mackenzie-Wood

The recent mine disasters in Australian coal mines have initiated an introduction of Self-Contained Self-Rescuer (SCSR) as component in the development of new escape strategies for miners. These self-contained self-rescuers are closed circuit, demand sensitive breathing apparatus that make oxygen available to the wearer for a nominal period of time. Their operation is completely independent of the surrounding atmosphere. Once properly donned, the SCSR can assist a miner to escape from an area containing smoke, toxic gases or an oxygen deficient atmosphere. The duration of a typical SCSR is usually taken at the point of complete collapse of the breathing bag which is accompanied by an increase in breathing resistance and inhaled levels of carbon dioxide. Because the oxygen consumption (V02) and the heart rate are correlated, a prediction of V02 and consequently the duration of an SCSR can be made by monitoring the heart rate. Thirty-seven volunteers participated in field simulated escape trials at four underground coal mines. The results from the field trials suggested that oxygen consumption depends on the heart rate, the body weight and exercise rating of the miner. All the volunteers were asked to fill out the questionnaires to evaluate the performance of the units. The miners indicated that they could tolerate the inhaled temperature without any difficulty to breathing resistance. A complete statistical analysis of the field results is also presented.

Feb 24, 1997

By M. Weatherspoon, S. Gebo, K. Prisbrey

Our objective was to develop a transfer function model of phosphate heap leaching for design, optimization and control. The procedure included analysis of time-lapse photography of a laboratory heap. Our experimental results confirm the predicted system transfer function kinetics. Our conclusion was that the transfer function and z transform that we have developed will allow us to control flow rate and pH online.

Jan 1, 2001

By K. Awuah-Offei

Energy efficiency has become significant due to cost and environmental considerations. Comminution and material handling have been identified as the two most energy intensive processes in mining. The objective of this work was to evaluate truck-shovel energy efficiency strategies using discrete event modeling. Energy audits and time and motion studies were conducted at a surface coal mine to acquire data. A discrete event simulation model of truck-shovel operations was built in Arena® and validated with the field data. The model was used to evaluate the effect of using a larger shovel, and optimizing truck-shovel matching on fuel efficiency. The results indicate that using a larger excavator increases the fuel efficiency of the operation while optimizing truck-shovel matching does not. However, using a larger shovel will lead to under-utilization of the shovel. This work shows the potential benefits of using discrete event simulation to model energy efficiency of mining operations.

Jan 1, 2012

By Vince Luongo

PROJECT DESCRIPTION The York Durham Sanitary System (YDSS) Interceptor in the Town of Richmond Hill located just north of Toronto, Ontario, Canada will see the construction of a tunnel extending along 19th Avenue for a length of approximately 3.8 Km from Yonge Street, east to Leslie Street and will have a minimum internal diameter of 2.1 m. t to Leslie Street and will have a minimum internal diameter of 2.1 m. The tunnel will connect into four shafts, for which two of the shafts will be constructed using the slurry wall construction method given the high water table and difficult ground conditions encountered at these locations. The two shafts noted as Access Shaft No. 2 and No. 3 were designed and constructed to meet regulatory conditions, which required a sealed shaft construction method. GEOGRAPHICAL PROFILE The ground conditions in the Toronto region consist predominately of glacial till, glaciolacustrine and glaciofluvial sand, silt and clay deposits, and beach sands and gravels. The shallow geological formation found in the project area consists of four types of deposits: Oak Ridge Morain deposits, Halton Till, Glacial lake deposits and Organic soils. The Oak Ridge Morain is the dominant deposit encountered along the tunnel alignment. This formation consists of three deposits: The Upper Till, Middle Sand and the Lower Till. Standard penetration tests (SPT) carried out in these deposits measured N-values ranging from 2 to more than 100 blows/300mm which indicate very loose to very dense soil conditions. The Middle Sand deposit will be the dominant feature within the slurry wall construction at access shafts 2 and 3. Access Shaft 3 The base of the slurry wall will be 20.5 M below the ground surface. Slurry wall excavation will be within peat and organic soils found at the upper 3 M, followed by 5 M of the Upper Till. The remainder of the excavation will be within the Middle Sand. The piezometric head elevation is found at the ground surface. Access Shaft 2 The base of the slurry wall will be 22.5 M below the ground surface. Slurry wall excavation will be entirely within the Middle Sand 2.The piezometric head elevation is found at 7 M below the ground surface.

Jan 1, 2007

By Roger L. King

Working in gassy ground conditions is an everyday occurrence for the U.S. coal mining industry. As tunneling operators begin to venture into projects that expose them to the additional hazard of potentially explosive atmospheres, lessons learned by the mining industry over years of experience should be transferred into this industry. This paper will present practices developed by the U.S. coal mining industry for dealing with the problem of excavating material in potentially explosive atmospheres. Procedures will be discussed that can be used to detect and quantify gas prior to mining that have application to the construction industry. Degasification or drainage practices, including predrainage from vertical and horizontal boreholes, will be discussed. Also, ventilation practices commonly used in the mining industry will be presented.

Jan 1, 1985

By J. D. Miller

Characterization of feed material with respect to expected concentrate grade and recovery is fundamental to the design of improved separation efficiencies and to achieve sustainable development in the utilization of our mineral resources. An important reference point for this characterization is the liberation-limited grade/recovery curve which represents the perfect separation, the best separation which can be achieved for a given feed material limited only by the extent of liberation. Now, liberation-limited grade/recovery curves can be determined based on 3D mineral liberation analysis of feed material. Thus, actual separation efficiencies can be compared to what might be expected for a perfect separation limited only by the extent of liberation. It is shown that 3D mineral liberation analysis based on X-ray micro CT (XMCT) is preferred to 2D section analysis which overestimates the extent of liberation. By way of example, procedures and experimental results are presented and discussed for feed material in the case of phosphate rock flotation.

Jan 1, 2009

By James J. Gusek

Passive-treatment systems that mitigate acid-rock drainage (ARD) from coal mines have operating since the mid-1980s. Large systems at metal mines are being contemplated. A 95L/sec (1500-gpm) capacity system is planned this year at an underground lead mine in Missouri. Mine, process and environmental managers need to understand how and why passive-treatment systems work. They must understand what operational limitations to expect, as well as the economics of construction and operation compared to the alternatives, like lime precipitation. Wetlands have been recognized as nature's method of improving water quality. Contaminant reductions can occur through the precipitation of metal hydroxides, sulfides and carbonates and pH adjustments. Local conditions, oxidation state and water and soil chemistries dictate whether these natural reactions will occur under oxidizing (aerobic) or reducing (anaerobic) conditions.

Jan 1, 1995

By L. Lacerda

Spray-on ground support membranes (GSM) or thin support liners hold today perhaps as much potential to impact underground (u/g) ground support operations as dry and later wet-mix shotcrete when introduced to mining in the latter part of the 20th century. This emerging technology has come a long way from the time the first single component experimental coatings were tested in the mid-1980s. Due to a number of factors, including occupational health risk and mine safety regulations, it has taken quite some time for the development of non-hazardous membrane products. However, at this junction most existing u/g mines that employ more conventional forms of ground support could benefit from evaluating GSM technology as a means of improving safety and the bottom line. The same is especially true for future mine developments. This paper describes Master Builders Inc.’s CS1251 GSM product and its implementation. It discusses the situations in which GSM may replace other forms of ground support. Furthermore, it evaluates GSM costs & safety issues and looks at present applications and the potentially bright future of this technology.

Jan 1, 2002

By K. S. Mortensen

The softwall mining system is a novel, new method of mining mineral deposits in soft, shallow, nonrock ground conditions. This method can mine the ore layer without substantially disturbing the existing overburden. The softwall mining system consists of machinery that is hydraulically controlled and powered, that can be buried (or used on the surface) to extract the ore or mineral from a layered deposit. The method is essentially an application of the longwall mining concept, modified for loose overburden and ore conditions, combined with hydraulic mining.

Jan 1, 2003

By M. A. Trevits, G. L. Finfinger

Various methods have been developed through US Bureau of Mines research to remove gas in advance of, during, and subsequent to mining. These include drilling horizontal or cross-measure boreholes from a mine opening, and vertical boreholes stimulated for drainage in advance of mining or for gob gas drainage. Techniques and equipment now exist that allow drilling a borehole at any angle to the vertical, and even along an arc. Stimulation treatments have also been developed that provide for increased gas production capability. This paper describes the long-term production history of five select gas drainage installations. The Bureau of Mines conducted or participated in four studies. The remaining study was conducted by the Equitable Gas Co. Principles of storage, release, and migration of coal bed gases The amount of gas contained within any given area of a coalbed depends on the coal's inherent storage capacity and the physical conditions of the coalbed. The gas storage capacity of coal is primarily a function of rank. As such, it cannot be affected by the presence of drainage holes (Kim, 1977). Certain physical conditions of the coalbed can, however, be changed that will affect the release and migration of gas. By pumping water out of the coalbed through the vertical boreholes, two important changes occur - pressure is reduced and water saturation is lowered. Reducing reservoir pressure releases gas as the coalbed adjusts and equilibrates gas to the change. Increasingly large amounts of gas are released for each incremental decrease in pressure. Lowering the water saturation level raises the permeability of the coalbed to gas and allows the gas to more readily migrate to the wellbore (Kisse and Edwards, 1975). For horizontal boreholes completed near mine openings, the coalbed has already undergone a pressure or water saturation reduction phase. This condition thus allows such boreholes to be highly productive with minimal water production. Case studies of coalbed gas production Pittsburgh Coalbed - Marianna mine 58 A methane drainage study was begun in July 1978 at Bethlehem Mines Corp.'s Marianna mine 58, Marianna, PA (Fig. 1). The work was conducted in a section of the mine that was advanced 1.5 km

Jan 8, 1986

By N. S. Kim

Economically favored Cr and Cu leaching out process from spent power plant fly ash (PPFA) had been investigated. PPFA, bearing of C, S, V, Ni, Cu and Cr, has been widely used as an assistant fuel in cement industry. Recent environmental regulation in S. Korea prohibits using PPFA as a fuel. Many researchers have also studied on extraction V and Ni from PPFA. Due to low concentration of V and Ni, 2% and 1%, respectively, economical and environmental friendly process could not be found. In this study, Cu and Cr have been removed in an economical way and which satisfied with KS Extraction Test. The rest unburned carbon, V2O5 and NiO2 in residue were found to be applicable for indoor and outdoor colored bricks or deodorant panel. Various parameters such as pH, lixiviates and time on leaching behavior were investigated in order to leach Cr and Cu remaining C, V and Ni. Keywords: Fly ash; Selective extraction; Ammonia; Deodorant panel

Jan 1, 2009

By Don Rose

INTRODUCTION A number of tunnels supported and permanently lined by steel-fiber-reinforced shotcrete (SFRS) have been built in North America in the 1980s. The material is more economical than, and technically equal or superior to, conventional shotcrete using wire mesh. The design and construction of SFRS-lined tunnels is straightforward, and only a few new design principles, laboratory tests or construction equipment modifications appear necessary in order to use this material. Modern tunnel Contractors may use cyclic drill-and-blast methods on some tunnels, with intermittent shotcreting as part of an orderly cycle. The Dry Mix method is most suitable for cyclic, intermittent, relatively small-scale shotcreting. However, modern Contractors excavating tunnels continuously using large long Tunnel Boring Machines (TBMs) or Roadheaders may prefer Wet Mix shotcreting on a mass production basis. In either case, the use of steel-fiber-rein¬forced shotcrete (SFRS) promotes the rapid and economical excavation of tunnels. The addition of microsilica will improve SFRS properties and reduce rebound, and is expected to become standard practice with SFRS in North America, as it now is in Scandinavia. HISTORICAL REVIEW Steel-fiber-reinforced shotcrete (SFRS) at the present time (1985) is essentially conventional shotcrete with straight or deformed steel fibers added, and in general SFRS for tunnel linings encounters the same problems that conventional shotcrete does. Shotcrete history is well known. The use of sprayed plaster on wire frames for mounting animal skins by Carl Akeley of the Smithsonian

Jan 1, 1985

By David Caiden, Geoffrey Fosbrook, Jaidev Sankar, Donald Phillips, Jon Hurt, Anil Parikh

This paper will cover the progress being made on Phase 1 of New York’s Second Avenue Subway line. It will include a description of construction progress on the first contract to be let, which consists of a 248 m (815 ft) long launch box, 3.9 km(2.4 miles) of TBM tunnels and a tunnel sump; the packaging strategy for the remaining work; and the progress through Final Design of the remaining packages, including the two large span rock cavern stations.

Jan 1, 2007