Search Documents

By Ralph Bernstein

The processing of earth observation sensor data by digital technology is almost two decades old. Only recently, however, has this technology become practical and economical. The reasons for this are interesting to analyze, and they provide some insight into what the future may bring. Some of the earlier activities and their limitations, current systems and their applications, and future technology direction are summarized.

Jan 1, 1979

By E. F. Divers

Adequate ventilation of coal mine working faces is the most important technique for controlling respirable dust and methane. Choosing the right technique presents some tough questions. US Bureau of Mines research has shown that to control respirable dust, you must contain the dust near the face, keeping rollback (turbulence) to a minimum. For methane, the most effective approach has been to use a blowing brattice, or tubing, and to create turbulence and disperse the face methane, allowing it to pass over the machine and into the return. It is immediately apparent that the two approaches may counteract one another, thus complicating the decision as to which system may be best for a given situation. At present. Bureau research has developed two successful machine-mounted face ventilation systems to meet these different needs and allow deeper cutting. The fan- powered dust scrubber is designed to control dust primarily associated with blowing face ventilation systems. The spray- fan controls methane on exhaust-ventilated sections.

Jan 1, 1987

By Thomas E. McNider

Preliminary studies were conducted at Jim Walter Resources, Inc. Blue Creek No. 3 Mine to determine the influence propane operated heaters exert on the mine ventilation system when two of three intake airshafts were heated. During initial use of the heaters, it was found that change in density caused by heating a portion of the air at two of three intake shafts altered under- ground air flow changes sufficient to be considered a violation of Part 75.322 of the Federal Coal Mine Health and Safety Act of 1969 as amended by Public Law 95.164. The primary concern was to accurately define the problem in order to derive a workable solution.

Jan 1, 1980

By J. N. Carras, N. W. Bainbridge

In order to further the understanding of spontaneous heating of longwall goafs a numerical model was developed, based on conservation principles applied to the transport of heat, water vapour and oxygen across the god Advective air flow into the goaf is caused by the differential air pressures across the god The air velocity field within the goaf area was computed using Darcy's law. The boundary and initial conditions concern air pressure, temperature and relative humidity. The oxidation rates and heat generation rates of the goaf materials required for the simulation were obtained from laboratory measurements. The main outputs of the model are temperature, oxygen and water contour maps, the rate of air leakage into the go4 velocity field and pressure distribution across the god. The model while still in its development stage, is able to simulate a heterogenous goafs constructed from different materials with different thermal and mass flow properties. Validation of the model by comparing its output with measurements from within goafs is required before the model can be used with confidence in a predictive sense.

Jan 1, 1995

By H. Soto, J. Jara, F. Nava, J. B. Hiskey, B. J. Scheiner

Laboratory tests showed that ozone can destroy free cyanide and weakly complexed cyanide (copper and zinc cyanides). The iron cyanide complexes were resilient to ozonation but they were effectively eliminated by precipitation with Fe (II) ions under controlled pH conditions. Tests carried out with effluents from a number of gold mills confirmed the results obtained previously in the laboratory. The industrial samples contained cyanide in the form of free cyanide and also complex copper, zinc and iron cyanides. Solutions that contained up to 184 mg/L total cyanide, after the ozone treatment analyzed only 2-3 mg/L dissociable cyanide and 50-90 mg/L CN(t) (accounted for by iron complexes). After precipitation with ferrous ions total cyanide was reduced below 1.5 mg/L. For most solutions ozone consumption ranges from 3 to 6 g per g of cyanide destroyed. However, certain impurities (such as SCN and S203 ), present in some effluents, increase ozone consumption and make it more difficult to reduce copper concentration to satisfactory levels.

Jan 1, 1993

By T. J. Durbin

At some surface and underground mines, control of ground-water inflow involves significant costs. These costs include the capital costs for installing a dewatering system, power and other costs to operate and maintain the system, and costs to treat and dispose of the water that is collected. To minimize these costs, design of a dewatering system utilizing wells has been formulated in terms of a nonlinear operations research problem using quadratic programming. Using this formulation, the locations, depths, pumping rates, and pumping schedules of wells are selected so as to minimize the total costs of the dewatering system.

Jan 1, 1993

By Changwoo Lee, Jan M. Mutmansky

Introduction Recognition of Coal Workers' Pneumoconiosis (CWP) as a major occupational disease has affected various aspects of the coal mining industry in the United States as well as in almost all major coal producing countries. Regulations related to the control of coal mine dust forced mine operators to modify their mining and ventilation practices. As the coal production record of the last 15 years shows, this had both direct and indirect impacts on the productivity and production costs. To identify the causes of CWP, many research efforts have been made through- out the world. Most of these studies were epidemiological in nature, attempting to pinpoint exposure and seam variables that affected the incidence of the disease. Other studies have been oriented toward the elemental and mineralogical composition of the coal dust in the mine atmosphere and in the miners' lungs. These studies indicate that there may exist some relationships between the characteristics of the coal mine dust and the prevalence of the disease. Some of the variables that are thought to affect the occurrence of CWP are the mass of the dust in the working place, the rank of the coal, the existence of certain trace elements, the free silica content of the coal, and the existence of other minerals in the respirable dust. A more complete description of these previous re- search studies has appeared elsewhere (Mutmansky and Lee, 1984). The behavior of particles in the human lung is known to be governed by their aerodynamic diameter, which is defined as the diameter of a hypothetical spherical particle with unit density that exhibits the same settling velocity as the given particle. Because of this fact, the aerodynamic size distribution of coal mine dust is one of the parameters to be determined along with the other physical, elemental, and mineralogical characteristics. The objective of this paper is to establish a strategy for providing coal mine respirable dust samples for characterization purposes using instruments that classify according to the aerodynamic diameter. In addition, several findings concerning characterization methods will be presented. Choice of Samplers Most of the gravimetric dust collection devices that can be utilized in a mine environment can be

Jan 1, 1986

By Steven A. Elmquist

INTRODUCTION R&D activities are needed, at a minimum, for a company's competitive survival followed in importance by the growth and diversification of the company. For most industrial companies, however, R&D is the business area that has been the most difficult relative to confident long-range financial commitments and effective control and relative to its value as a long-term investment. Investors look not only at the current profitability of the company but increasingly at the plans, actions, and quality of the personnel in position to improve the market position and profitability of an organization. "The strongest predictor of investment value is the degree of innovation of the 'company.' I believe this is true of both strategic planning and R&D activities." R&D is the lifeblood of a company's future. If this basic premise-R&D for survival and growth-is believed to be true, why is it necessary to "Sell R&D in your organization? My personal experience, in a number of organizations, is that R&D budget is perceived as a business element area that could be delayed or reduced to improve the bottom line during difficult business conditions. I believe the following quote speaks volumes about this subject-"There is only one thing I know for certain about research, and that is it costs money-lots of it." -Unnamed, Hard- headed Financial Executive. A business must make money and be profitable in order to maintain and create jobs, pay taxes, cover working capital and costs of goods sold, and most importantly, create value for its shareholders. The foremost element of selling R&D, therefore, is to consistently demonstrate the R&D group's contribution to the bottom line.

Jan 1, 2004

By Gerrit V. R. Goodman, Fred N. Kissell

The Bureau of Mines has evaluated the effectiveness of the safety elements used to prevent tunnel methane explosions. These fa1l under the general categories of better ventilation, better gas monitoring, reducing ignition sources, and improved worker training. For this evaluation, a technique called fault-tree analysis was used to analyze questionnaire responses from 27 tunneling experts. This analysis allowed us to rank the effectiveness of each safety element, and indicates where money is best spent to reduce the chance of a methane explosion. Results indicated that large decreases in the explosion hazard only take place with the simultaneous application of several elements. Most of these involve a human component - the everyday vigilance and awareness of those working underground.

Jan 1, 1991

By Jung-Hum Lee, Young-Joon Lee, Eui-Joon Hong, Seon-Hong Kim, Chan-Dong Kim, Keon-Woong Jeong, Ki-Lim Kim

"Subsea tunnel needs to be built over 50km long to connect between nations and continents. However there are only 19 tunnels longer than 5km in Korea, and there is no history of constructing and operating a tunnel longer than 50km. As the concept of a subsea tunnel, which withstands high water pressure and has an extremely long length is completely different from that of a land tunnel, all kinds of the latest technologies for tunnel construction are required such as survey and analysis of geology, design and construction under high water pressure, ventilation and prevention of disasters within an ultra long tunnel. Therefore, this paper describes the determination of tunnel cross-section under a high speed railway, structural stability, ventilation and fire safety under construction and operation, etc. through the virtual project for the length of 108km subsea tunnel under high water pressure of maximum 20bars from Honam to Jeju island in Korea. 1. INTRODUCTION The Honam-Jeju virtual project is subsea tunnel project to link from Honam(land) to Jeju(island) extending the currently operating Honam high speed railway line, and the same express train(t=18, design speed 350km/h, total train length 200m) operating at Honam line is applied in this project. As Honam-Jeju site is approximately 80km in straight distance with 160m maximum depth, subsea tunnel project should determine the various issues such as air quality/ventilation, aerodynamics, temperature, drainage, fire & life safety, structural stability. Figure 1. is the plan of subsea tunnel, with be constructed using Shield TBM. This double tube-Single track is composed of cross passages (every 350m in general section and 40m in emergency station), service tunnel, pressure relief ducts (every 250m), cross-over tunnels, shafts and emergency stations. 2. ALIGNMENT AND SITE CONDITON This project is planned as an ultra long tunnel of total length more than 105km via existing islands between Honam and Jeju island because straight alignment requires an artificial island which has high cost and construction risk, by deep water depth, though this is the shortest distance (see Fig 2). Water depth and topography in project site is divided into two blocks by Chuja Island. In first block to Chuja Island, depth of the water is 40m on average and maximum 60m, which indicates gradual change of water depth relatively. Also, outcrop bedrock is widely distributed near island."

Jan 1, 2016

By W. Jacobi, F. Steinhausler, A. C. James

INTRODUCTION In 1979 the Committee on Radiological Protection and Public Health of the Nuclear Energy Agency (OECD) defined a programme of work needed to improve radon dosimetry and monitoring. A Group of Experts in this field was established by the NEA and at the first meeting of the Group the authors were designated an initial task with the following terms of reference:- To review dosimetry of radon, thoron and their daughters, and in particular:- - to examine analytical models for the assessment of dose to individuals who are exposed to aerosol mixtures of these nuclides; - to examine the state of knowledge of the characteristics of aerosol mixtures of these nuclides and other factors that influence the dose to the lung, and identify those parameters which should be measured for dosimetric purposes in radiological surveillance programmes; - to identify areas where further study or research are needed. In this presentation we attempt to examine, with these objectives, the relationship between exposure to radon and thoron daughter aerosols expressed in terms of the working level month l (WLM), or its SI equivalent, and dose accumulated by sensitive tissues of the lower respiratory tract. Over the past two decades many attempts have been made to calculate the lung dose equivalent to l WLM exposure in mine atmospheres, usually in terms of the maximum dose to basal cells in a small part of the bronchial tree. The calculations have employed variously detailed models of airway anatomy, aerosol deposition, ciliary clearance and dosimetry of tissue at the bronchial surface, and are well reviewed elsewhere (Walsh, 1970; UNSCEAR, 1977; Jacobi, 1977; Fry, 1977). They agree in the conclusion that basal cells in segmental bronchi (between about the third and fifth bronchial generations) receive the highest dose, although estimates of this dose differ by more than an order of magnitude, ranging from about 0.2 to 12 rads per WLM (2 mGy to 120 mGy). The most critical parameters of these models are the assumed depths of basal cells below the bronchial surface and the fraction of the WL carried by free ions. When more realistic values of these parameters are substituted (Jacobi, 1977), the dispersion in calculated maximum doses to basal cells is reduced to give a much smaller range from about 0.3 to 1 rad/WLM (3 to 10 mGy/WLM). The parameters and methods employed in these various models, however, remain too diverse to infer the sensitivity of the dose conversion to practical variations in aerosol characteristics and the additional factors determining lung deposition and clearance. We have therefore taken the approach of developing newer models (Jacobi and Eisfeld, 1980; James et al, 1980) that can encompass the range of available experimental data on the physical and biological behaviour of radon and thoron daughters and also accommodate the different interpretations that can be put upon them. We have paid particular attention to the averaging of dose over tissues of equal sensitivity in the lung

Jan 1, 1981

By Rossen Halatchev

The production sequence optimization of open pit mine is a procedure that reflects the exploitation conditions over life of mine. These conditions are determined by the geological characteristics of the deposit, requirements of the mining and processing technologies and economic parameters of the exploitation. From a technological point of view the production sequence optimization deals with two aspects - spatial and time. Each of them plays a tremendously important role in searching for the optimum solution of the problem. This paper treats the time aspect of the production sequence optimization. This aspect is revealed in the context of the problem of the working zone formation of the open pit mine in time. The problem formulation places an accent on the determination of the theoretically possible time distribution of the waste and ore quantities of each bench of the open pit mine. A mathematical solution to the problem has been developed based on combinatorial analysis. The solution provides a multi-variant investigation of the production sequencing with the use of an optimization model developed as a linear programming formulation. The model objective function uses the Net Present Value as a criterion for assessing the effectiveness of production sequencing. A case study is provided for the conditions of Assarel copper open pit mine (Bulgaria) to illustrate the applicability of the approach. The results obtained reveal the complex nature of the variation of the Net Present Value as a function of the mining factor.

Jan 1, 2002

By James R. Piper

Cumulophyric feldspars, of varying morphology, carry myrmekitic quartz interstitially between microperthitic feldspar lamellae. The size, coarseness, and morphology of these crystals, together with concordant foliation features constitutes evidence that they are a product of primary crystallization, formed prior to eruption from a vent. These crystals occur preferentially along 2 - 5 mm thick tan, vesicular to compressed alteration bands intercalated with more densely welded light grey bands. In perlite with quartz at or below a 0.1% threshold, megascopic feldspars are less than 1%. Perlite with quartz above this level has megascopic feldspar concentrations >3%, typically in the 5-20% range.

Jan 1, 1991

By Kadri Dagdelen, Thys B. Johnson, Salih Ramazan

Long-term production scheduling design is a very important part of mining because it determines the economic outcome of a project There have been many attempts to solve the optimum pit scheduling problem, but there has been no success in developing a scheduling method to give optimum results in maximizing net present value of a mining project. Open pit production scheduling problem can be formulated as a mathematical programming problem and solved using Mixed Integer Programming technique. However, it is not possible to solve the formulation within a reasonable time since the number of integer variables required for the mathematical model is too great to do that by today's available computer technology. There- fore, a methodology is required to combine, or aggregate, the mining blocks and to decrease the number of integer variables in scheduling without losing the optimality. Therefore, the fundamental tree concept was developed in this paper to combine the blocks. A fundamental tree is defined as any combination of blocks such that: 1. the blocks can be profitably mined, 2. the blocks obey the slope constraints and, 3. there is no subset of the chosen blocks that meets 1 and 2. A Linear Programming (LP) formulation is developed as a mathematical model to find a set of fundamental trees that exist for a deposit. Since the blocks are combined to form the fundamental trees, the number of variables required for the scheduling model is decreased significantly. This decrease in the number of variables makes it possible to mathematically formulate the multi-time period scheduling problem as a Mixed Integer Programming (MIP) model. A case study is performed on a multi-mineral copper deposit in Peru, South America. NPVs of annual after-tax cash flows generated based on the schedule provided by the "Fundamental Tree Algorithm" is compared with NPVs resulted from the schedules coming from three of the computer packages presently available to the mining industry. These are Mintec's M821V, Earth- work's NPV Scheduler, and Whittle's Milava open pit mine schedulers.

Jan 1, 2002

By Christoph Wels, Michael Royle, Shannon Shaw

Intrinsic remediation is the effect of natural attenuation mechanisms - dilution, dispersion, sorption/precipitation and biodegradation - reducing contaminant concentrations in ground water to specified levels at predetermined compliance points in the aquifer. Current monitoring and modeling for post closure was used to assess the current and long-term potential of intrinsic remediation of contaminated seepage originating from a large reactive (sulfidic) tailings impoundment near Questa, New Mexico. It is concluded that the natural attenuation mechanisms of precipitation within the tailings (as a result of buffering) and dilution/dispersion within the aquifer are currently active and likely sufficient to reduce contaminant concentrations to below state standards in the long-term. Other natural attenuation mechanisms such as sorption and biodegradation within the receiving aquife4s) were not assessed here, but are likely further reducing contaminant concentrations. Active interception and recovery of the seepage water is being maintained until monitoring demonstrates that intrinsic remediation has successfully achieved the level of water quality control required.

Jan 1, 2000

By Derek M. Hutchinson, Don Zeni

The construction of shafts by blind drilling has been made cost effective by advances in technology and experience. The techniques of blind shaft drilling are discussed and a brief history presented. A recent use of blind shaft drilling to access a small gold ore body in Australia is described. Finally, the most recent developments in drilling machinery are reviewed together with possible applications in new and existing mines.

Jan 1, 1987

By Jim Finley, Adam Bedell, Eric Schrader

The CSO 52 Storage Tunnel and Pump Station project consists of 4,700 ft of hard rock tunnel, 2 intakes, and a 4 MGD wet pit pump station. During the geotechnical investigation, it was determined that the host geology contained abundant suldes. The purpose of this paper is to detail the investigation and subsequent determination that acid producing materials would affect the project during construction as well as long-term exposure of tunnel lining and permanent components during the operational life cycle of the tunnel and pump station. Details regarding the interaction between tunnel components and the acid producing material are also provided.

Jun 23, 2024

By David R. Maneval

In 1956 the Legislature of the Commonwealth of Pennsylvania created a "Coal Research Board" in the Department of Mines and Mineral Industries. Over the years through amendments to the original legislation, the scope of authority for research has been expanded from the narrow area of improving and increasing the utilization of coal to covering all aspects of coal technology and any other area of interest which would be of value to the coal industry. In January of 1964, the Board commenced a vigorous program using appropriated funds and funds donated by the coal industry to finance a research program devoted to seeking solutions to the mine drainage problem. A review of published literature on the treatment of mine drainage indicated that much work done up to that point in time concerned only the mechanism of mine drainage formation and theoretical chemistry. Very few applied, developmental, or engineering studies had been devoted to finding practical solutions to the problem of polluted waters being discharged from active or abandoned mines. Projects were therefore undertaken on a wide variety of more utilitarian approaches. This paper will discuss briefly some of the pollution abatement approaches which have been funded by the Coal Research Board of this State, and will describe in some detail a multistage flash evaporator treatment plant now under construction.

Jan 1, 1970

By T. B. Szwilski

ISO 14000 series are voluntary international standards that address environmental management system standards, environmental auditing, environmental labeling, environmental performance evaluation, and life-cycle assessment. An environmental management system (EMS) is a facet of an organization's structure that addresses the immediate and long-term impact of a company's products, services, and processes on the environment. Many companies in the United States are taking a cautious wait-and-see approach before embracing ISO 14000. A few mining companies are reviewing the standards and using them as guidelines. The paper outlines the status, possible benefits to the mining industry, and options available to a company wanting to become involved in the ISO 14000 standards.

Jan 1, 1997

By C. L. McKenzie, R. A. Heig

The design and operation of metallurgical laboratories is discussed. Laboratory size, general laboratory equipment and metallurgical staffing are discussed from a standpoint of desired laboratory results.

Jan 1, 1986