Search Documents

By J. Larsson

In the pursuit of increased safety the mining industry has worked to develop systems for remote control and autonomous operation of both stationary and mobile equipment. This paper reports on a newly developed system for teleoperation and autonomous tramming of LHD (Load-Haul-Dump) mining vehicles that not only increases the safety of the operators, but also has the potential to increase productivity.

Jan 1, 2010

By R. Wu, R. Howell, J. Dase

Turquoise Ridge is an underground gold mine located in the Potosi Mining District, approximately 64 km northeast of Winnemucca, Nevada. Turquoise Ridge Underground is accessed via two shafts and a system of internal ramps and utilizes underhand drift and fill mining methods with cemented rockfill. The mine also employs mechanical mining as well as sill benching as mining methods. Ground conditions at Turquoise Ridge Underground are poor, and the Rock Mass Rating (RMR) may be less than 20, or very poor, in ore headings. Current production rate is 2,700 tonnes of ore per day. Key challenges in increasing production levels and reducing costs are the development of sufficient stoping areas and the transition from top-cut development to undercut stoping. Completion of the infrastructure development in the North Zone is necessary to achieve and optimize higher production levels. The #3 Shaft project is well underway and is expected to be commissioned in mid. 2022. The shaft will drastically decrease the haulage requirements in the North Zone

Mar 2, 2022

By K. Fuenkajorn

Geomechanics and geohydrological considerations for the seal design for mine openings are presented. Design guidelines derived from laboratory and in-situ experiments are proposed. The results suggest that seal design, specifications and material selection should be site-specific. Performance requirements for a specific seal location should be identified. Evaluation of sealing effectiveness should be made on the entire seal system, i.e. seal, seal-rock interface, excavation-induced damage zone and the surrounding rock.

Jan 1, 1997

By L. M. English

In the past 30 years, the research arena has changed significantly in all fields, mining included. The relative representation of the topics of research, how the research is performed, and who has performed the research have all changed significantly over these decades. Although there are a lot of subjective ideas concerning these changes, and there is a fair amount of anecdotal "analysis," there has been no actual study of these trends to verify the facts. The period studied is divided into six five-year periods for the purposes of comparison. Some of the trends analyzed are as follows: ? Co-authorship ? Research areas ? Research sponsors ? Cooperative efforts

Jan 1, 1995

By L. Yuan, R. A. Thomas

"Atmospheric monitoring systems (AMS) have been widely used in underground coal mines in the U.S. for the detection of fire in the belt entry and monitoring of other ventilation-related parameters such as airflow velocity and methane concentration in specific mine locations. In addition to an AMS being able to detect a mine fire, the AMS data has the potential to provide fire characteristic information such as fire growth (heat release rate) and exact fire location. This information is critical in making decisions regarding fire-fighting strategies, underground personnel evacuation, and optimal escape routes. In this study, a methodology was developed to calculate the fire heat release rate using AMS sensor data for carbon monoxide (CO), carbon dioxide (CO2), and airflow velocity based on the theory of heat and species transfer in ventilation airflow. Full-scale mine fire experiments were then conducted in the Pittsburgh Mining Research Division (PMRD) Safety Research Coal Mine using an AMS with different fire sources. Sensor data collected from the experiments were used to calculate the heat release rates of the fires using this methodology. The calculated heat release rate was compared with the value determined from the mass loss rate of the combustible material using a digital load cell. The experimental results show that the heat release rate of a mine fire can be calculated using AMS sensor data with reasonable accuracy. INTRODUCTION Fires at different stages generate different gases and smoke toxicity hazards. When fires occur in underground mines, a significant amount of toxic gases and smoke enter the mine ventilation system and are carried throughout the mine ventilation network, increasing the hazard potential for personnel even if far away from the actual fire. Although fires that develop to the point of rapid flame spread pose imminent hazards, fires in their smoldering, pre-flaming stages can also contaminate the mine atmosphere with debilitating levels of smoke and toxic gases. The most important parameter for evaluating the fire hazard in mines is the heat release rate (HRR), which is directly related to the rate at which heat, smoke, and toxic gases are produced and transported by the ventilation system, and provides an indication of the time available for escape or firefighting [1]. The HRR is also an important input parameter to mine fire simulation models. Measuring the HRR of an actual fire can be a difficult task. Early experimental measurement of HRR focused on the heat output as represented by the temperature of the product gases. In ASTM E1321 (LIFT test), an array of thermocouples was positioned in a duct which captured all gaseous combustion products to measure their average temperature. This approach assumed the flow is adiabatic, which is never a reality. Significant progress on measuring HRR was made when Huggett showed that, for most common materials containing C, H, O, and N, the average heat release per unit mass of oxygen is 13.1 MJ/kg O2 [2]. Thus, the oxygen deficit is a measure of the HRR in the flow that the duct captures. This approach is termed oxygen consumption calorimetry (or the oxygen consumption method), and is widely used in the fire protection community."

Jan 1, 2017

By A Pettersson

LKAB owns and operates two of the largest underground mines in the world in Northern Sweden. In Malmberget, with a production capacity of about 30,000 t/day of iron ore, the current main 815 m haulage level is rapidly approaching the end of Its life and plans are being made for its replacement on the 1000 m level. Due to the separation of the orebodies, trucks have been chosen for transporting the ore from the orepasses to the crushers. The trucks currently in use have a capacity of 120 tons. To increase the efficiency of the loaded haul, the new main level will have a favorable slope from the drawpoint locations to the crushers. From the new level the crushed ore will be transported by conveyor to the 815 m level for hoisting to the surface. The paper discusses the planned mining and transportation system.

Jan 1, 1998

By III Feeley

The U.S. Department of Energy is supporting the engineering development of three advanced physical coal cleaning technologies--selective agglomeration, advanced flotation, and advanced cycloning--capable of significantly reducing the pyritic-sulfur content of U. S. coals. The objective of this activity is to provide the coal production and electric-utility industries with a cost-effective option for addressing the SO2 emission reductions required by the 1990 Clean Air Act Amendments. A secondary objective is to evaluate the potential of advanced coal cleaning for removing trace elements that are precursors to the formation of hazardous air pollutants. This paper will summarize the status of the three advanced physical coal cleaning engineering development projects.

Jan 1, 1993

By A. Benchekroun

The phosphate mining industry is confronted everywhere in the world with financial difficulties and low prices which prohibit further investments and development of new mines even in regions with a comparative cost advantage (North America/ North Africa/ and Middle East). But old mines are being progressively exhausted/ and if no replacement mines come on stream in the near future/ we may soon find ourselves (around the year 2000) with a global annual production capacity of 160 million tonnes of marketable phosphate rock instead of the capacity of 200 million tonnes existing today. Unless prices improve/ phosphate rock/ a non-renewable resource and a vital commodity to world agriculture/ may turn to be in short supply to world fertilizer industry. Whatever the extent of recovery of fertilizer demand/ the expected decline of the production capacity during the 1990 I s is bound to cause the disappearance by the year 2000 of the important surplus characterizing today the supply/demand balance.

Jan 1, 1995

By Dragomir Gospodinov, Savka Dineva

A surprisingly large mining-induced seismic event occurred in the LKAB Kiirunavaara Mine (Sweden) on 18 May, 2020 at 03:11 (local time). The estimated moment magnitude was 4.2. The event caused extensive damage in a large section of the mine. The production in the area is not yet resumed, even by the beginning of 2022 (~20 months after the event). The Kiirunavaara Mine has one of the world’s largest underground seismic systems with approximately 253 geophones. The in-mine records of the event showed a very complex character with a several sub-events. The event was also well recorded by seismic stations out to over 9,000 km distance. Data from the underground and regional seismic systems were analysed to define and compare basic source parameters such as hypocenter location, seismic moment, as well as the seismic moment tensor. The data from the in-mine seismic system was used to study the development of the seismic process and to define elementary seismic sub-sources together with the official hypocenter location.

Apr 26, 2022

? World industrialization, increased urbanization, and population growth are driving a sustained demand for minerals, metals and coal. Energy demand is expected to increase significantly in the coming decades - placing even more emphasis on supply, security and environmental impact issues. ? Several countries are taking steps to nationalize their own resources thus safeguarding their supplies and reducing exports of natural resources. ? Understanding the future availability of critical minerals requires a global perspective. It is essential to know where deposits are located, their reserves and resources, the technologies necessary for production, and the costs of producing and transporting the products to consumers. ? As mining companies look to maintain or increase their operating capabilities and increase their mineral resource bases, the search for commodities expands beyond developed terrestrial regions of the world, to include marine resources. (Figure 1) Operating challenges in these locations include finding skilled workers, building infrastructure, improving recovery technologies and practicing sustainable development.

Jan 1, 2011

By G. F. Revey

All underground operations have limiting factors that influence overall profitability. Hoisting, hauling, available headings, labor, milling capacity and other factors limit how much material can be removed from an underground mine. Consequently, when mines use limited labor to handle the additional rock from overbreak and to perform extra ground support tasks, productive activity is replaced by non-productive work. Mining economics are further penalized when overbreak causes dilution of ore grades. This paper reviews organizational systems that mines have used to create environments which foster the creation of successful overbreak control programs. Actual case histories document the various quality improvement techniques, worker incentives, and practical project management systems used by these mines. A brief review of controlled blasting technology sources and overbreak measurement tools is also included.

Jan 1, 1997

By John A. Rajala

The water chemistry of the froth flotation pulp is one of many parameters which can affect the flotation process. The fluid may contain certain inorganic salts which, along with increased ionic strength, can produce undesirable flotation depression or activation. A source of a salt could be the use of calcium chloride to prevent freezing in ore cars, chutes, and bins (Anon., 1980). Alternately, the salt or salts could be initially contained in the water as in the case of sea water and some brackish waters. These salts may become more concentrated because of the need for recycling of plant water due to environmental regulations and/or economic considerations (Davis, F.T., et. al., 1976). The presence of inorganic salts in flotation pulps and their effects upon the recoveries and surface chemistries of different oxide minerals have been the object of various studies. Some researchers (Fuerstenau, D. W. and Raghavan, 1976; Fuerstenau, D. W. and Modi, H. J. 1960; Kulkarni, R. D. and Somasundaran, P., 1977) have reported that addition of a salt can increase or decrease flotation recovery depending upon the particular system.

Jan 1, 1982

By Susan G. Bilhorn

A number of studies have been conducted in active and inactive mine environments using continuous monitoring and data acquisition systems to detect various parameters. In addition to the information obtained for research purposes, these monitoring systems can provide a means to remotely collect required information (such as radon daughter concentrations and air velocity) and control various conditions (such as fan operation and air door position) in numerous working sections of an active mine. Selection of detector locations and placement, which are critical to obtain the information and control desired while not inhibiting mine operations and influencing the detector readings, are covered in this paper.

Jan 1, 1984

By Manuel Viveros J.

This paper will deal with the type of rocks so called evaporites, which are sedimentary rocks produced by water evaporation from seas, lakes or marginal lagoons, in warm and arid climates. Salts derived from these deposits are precipitated according to their solubility; that is, the more soluble precipitates first, overlain by other sediments like silts, shales, limestones, sands, etc. The most common evaporites, according to their chemical composition, are : Chlorides Sulphates Carbonates Nitrates Borates Common salt, or halite, sulphates like anhydrite and gypsum, are the most important. Potassium chloride (silvite and carnalite) and potassium sulphate are of great commercial value.

Jan 1, 1974

By John Matthews

During 1982 and 1983, it became increasingly clear that North River No. 1 Mine would have to buy a set of replacement longwall shields. Despite extensive efforts to make improvements, the shields that were in place at that time were incapable of holding the roof. North River Energy had limited experience in specifying and acquiring longwall roof supports, but a great deal of experience with our conditions and needs. We there- fore compiled a shield evaluation method that uniquely responded to our situation. The resulting system emphasized teamwork among operating, maintenance and engineering personnel. The charge from management was threefold: select shields to support maximum expected loads, optimize face operations, and pay attention to detail. Final selection was made objectively, based on all available information. We chose a 5516 KN (620 tons) support with a minimum yield load density of 760 KN/m2 (7.9 tons/ft2). This paper reviews our process of specification, design, prototype testing, and fabrication, and offers some relevant suggestions.

Jan 1, 1986

By Edwin R. Phelps

Good morning ladies and gentlemen - today I am in an enviable position for two basic reasons - No. 1, since I am first on the program, the audience should start out awake because those that partied too much last night are still asleep, but in their room, not here. No. 2, since copper, iron, and mining technology are not competitive, the veracity of my statements will not be questioned. Most such meetings I attend are based on the subject of energy and the coal industry does have competition from oil, gas, hydro, and nuclear. However, to counteract this advantage I am the usual engineer with a limited vocabulary by schooling, and the remaining vocabulary almost completely eliminated due to the presence of ladies. In relation to the past of the coal industry, we have not only suffered the competition of other energy sources mentioned before, but in addition have in the last 25 to 30 years been required to meet the demands of a vastly changing market. To explain this statement, I am sure many of you can remember 30 to 40 years back when most homes were heated by coal furnaces or stoves and shudder to recall the shoveling of coal into the fire and the carrying out of ashes with the attendent manual labor dust. Now this space heating portion of our sales has almost become non-existant due to an almost universal switch from coal to natural gas, oil, and electric heating. Actual figures show a decrease from 119 million to less than 28 million tons per year in less than a twenty year span. Also, most of you can remember the coal burning steam locomotives and the tremendous volume of coal they consumed and then the very rapid change to the diesel-electric locomotives, incorporating improved large diesel engines driving D C generators and electric drive motors, which resulted in cheaper motive power. This change over was so complete that the annual tonnage of coal dropped from 125 million to less than 2 million tons in 15 years. 'Actually, now it requires some considerable interrogation and traveling to find a locomotive still operating on steam.

Jan 1, 1968

By Péter Siklósi, János Zámbó, Károly Solymár

It is fundamentally important to evaluate bauxites in a realistic, commercial way on the basis of the processing technology both for the supply of existing alumina plants and for the designing of new ones. The evaluation system developped by ALUTERV-FKI consists of chemical, mineralogical, texture and technological testing. The commercial value of bauxites is basically determined by their available alumina content and the caustic soda consumption required for their processing. However, their contaminants have to be taken into consideration, too. The commercial value of bauxites also depends on the processing technology and their possibly unfavourable chemical and mineralogical composition can be /at least partially/ compensated by R&D efforts. The selection of the optimum processing technology and the effects of further developing the same are demonstrated on monohydrate bauxites containing goethite and carbonates. Some of the technological solutions /desilication or deironing of bauxites, hydrothermal treatment of the digestion residue / make at the same time possible the complex processing of the bauxites, the profitable utilization of their main components.

Jan 1, 1984

By James M. King

Analytical models for transient groundwater phenomena, such as those of Theis, Cooper, and Jacob, are important but often limited tools for aquifer evaluation and drawdown prediction. Most were developed using simplifying assumptions which compromise their treatment of complex boundaries and most also contain functions that are mathematically complex and difficult to solve explicitly. Examples of such functions are the Bessel functions, the exponential integral, and similar well functions for leaky confined and water table aquifers. This paper describes the joint use of simple numerical techniques and numerical approximations of these functions to extend many analytical models beyond their conventional applications. The enhanced analytical methods represent many hydrologic problems more easily and realistically, permit a wider range of application, and often provide insight into the response of pumped groundwater systems without the need to resort to more complex numerical flow models. Use of the enhanced analytical methods usually requires the use of microcomputers due to the large number of computations. Examples presented here are the development and extension of type curves and the determination of drawdown distributions.

Jan 1, 1984

By Z. T. Bieniawski, D. A. Newman

The Geomechanics Classijication (RMR System) (Bieniawski, 1979) was modified for entry and roof support design in underground coal mines. Adjustment multipliers were introduced to incorporate the influence of high horizontal stresses and the roof support reinforcement into the existing classification system. Sixty- two case histories of standing and fallen mine roof were collected from two mines in the northern Appalachian coalfield. Twenty-seven engineering and geologic parameters were recorded for each case. A partial correlation analysis was carried out on the cases to establish which parameters have a significant im- pact on the stand-up time of supported coal mine roof. Survival analysis, a statistical technique used in medical research to assess the effect of a drug or treatment on a patient's life expectancy, was conducted together with stepwise multiple regression to derive values for the adjustment multipliers. A practical example is included to illustrate the application of the modified Geomechanics Classification to underground coal mine design.

Jan 1, 1987

By Alfred Jr. Petrick

Modelling of cash flows and calculation of net present value of rate of return over the expected life of a mine/processing unit continues to be the accepted basis for mineral investment decision-making. The computer and spreadsheet programs have greatly improved ability to perform sensitivity and risk analysis, hence our ability to deal with key analytical problems. These problems of cash flow analysis result from the necessity of forecasting an uncertain and risky future. Cash flow models begin with the critical assumption of a "design basis", then integrate all of the variables relevant to the investment decision including forecasts of price, cost, taxation, financial conditions, and company strategy. Alternate "scenarios" portray possible future outcome of the investment decision. The potential for straying from reality is enormous. The computer has eliminated the time consuming hand calculations from the cash flow analysis, but the analyst still struggles with the risk of trying to predict "how the project will really turn out".

Jan 1, 1991