Search Documents

By Feridon Ghadimi, Saeed Mojeddifar, Massume Khavari

Separation of geochemical anomalies from background is an important and essential issue in the exploration of mineral deposits. Statistical methods are used to separation of anomaly from background. Fractal/multifractal and singularity methods are very suitable for the separation of weak anomalies. For interpolation, various methods could be used such as most distance-weighting methods, kriging, spline interpolation, interpolating polynomials, and finite difference methods. This paper addressed application of multifractal techniques together with finite difference procedure to detect the anomalous regions. Fractal models such as concentration–area, spectrum–area, and singularity index model were selected to identify Pb–Zn anomalies. In this research, 170 samples from 33 boreholes were taken in the Haft-Savaran area and analyzed for determination of Pb–Zn anomaly. Singularity method was a suitable method for separating Pb and Zn anomalies. Also, the results showed that the geochemical anomaly has occurred along NE–SW trend and is consistent with the sulfide mineralization process and the faults of the region.

May 18, 2020

By A. O. Drysdale

From a mining point of view the Portland Cement Industry falls logically into the Industrial Minerals Division. Portland Cement manufacture requires four principal materials, lime, silica, alumina and iron. The usual source of lime is limestone. Silica sources include clay, shale, quartz, sandstone and sand. Alumina is usually provided by selecting a silica source with a suitable alumina content such as clay and shale. "Cement Rock" is occasionally found in which all four ingredients are found in natural combination or sufficiently close that only minor adjustments are required. In the absence of iron oxides a white cement can be produced. All raw materials used in Canada contain some iron and in most plants further minor quantities of iron are added to promote fluxing, hence the typical grey colour of Portland cement. The modern period in cement manufacturing started in 1824 when Joseph Aspdin of England patented a process for the manufacture of a modified hydraulic cement which he called "Portland Cement". Hydraulic cements are cements that harden under water. Although natural cements, made by calcining and grinding natural argillaceous limestone were produced in Canada as early as the 1830's, Portland cement was not produced in Canada until 1890, about 18 years after it was first made in the United States.

Jan 1, 1964

By Yi Luo, Jian Yang, YUJIA LIAN

Scale physical models, constructed according to the principle of similarity theory, have been widely used to simulate the mining disturbances to surrounding strata and to evaluate the effectiveness of implemented ground control techniques. This technique has also been used for studying mining-induced surface and subsurface subsidence. The movements of the observation points installed on the physical model at different mining stages are currently measured using total station which is time-consuming and inaccurate especially on small scale models. A photogrammetry-based measurement system has been developed. During a physical modeling process, photos of the model can be taken during the simulation process reducing survey time from hours to a few seconds. A program, Photogrammetry Analysis for Physical Modeling of Mine Subsidence Process (PAPMMSP), developed based on photogrammetric principle is used to quickly identify the installed observation points and accurately determine their coordinates. The measurement accuracy is well under submillimeter level—an ultra-important advantage as any measurement errors in coordinates are magnified by the model dimension scale (commonly 20 to 400). A physical modeling case of subsurface strata movements and deformations associated with longwall mining operations is presented in the paper to demonstrate the functions and capabilities of the developed photogrammetry program.

Aug 11, 2020

By H. Jung, J. Kim, Y. Lee, Y. Seo

"Shale gas has become an increasingly important source of natural gas supply in North America and around the world. Horizontal drilling and multi-stage hydraulic fracturing are the two key enabling technologies for the economic development of these shale gas reservoirs. It is believed that gas in shale reservoirs is mainly composed of free gas within fractures and pores and adsorbed gas in organic matter (kerogen). It is generally assumed in the literature that the monolayer Langmuir isotherm describes gas adsorption behavior in shale gas reservoirs. In this work, we have analyzed several experimental measurements of methane adsorption from the Horn River Shale core samples that obey the Langmuir isotherm. INTRODUCTION In nature, gas shales are characterized by extremely small grain size, extremely low permeability on the order of nano-Darcy (10-6 md), small porosity, and high total organic carbon (TOC). Shale can serve as both source and reservoir rock. The amount of gas in place in shale is strongly affected by the TOC, clays, and the adsorption ability of methane on the internal surface of solid (Martin et al., 2010). Since a considerable amount of gas in shale reservoirs is adsorbed, investigation of gas adsorption can provide critical insights into evaluation of well performance and reservoir characterization. Generally, natural gas in shale reservoirs is stored as free gas in both larger mineral pores and natural fractures, as well as adsorbed gas within organic matter (Leahy-Dios et al., 2011). EXPERIMENT METHOD & THEORY Adsorption Experiment Several experiments were carried out on 9 shale core samples obtained in a vertical well drilled within Horn River basin (Figure 1). The CH4 adsorption isotherms were measured for the different depth. In order to measure the amount of adsorbed gas, the high pressure Belsorp-HP equipment applying volumetric method was used. The temperature was kept at 298 K and pressure was increased up to 18 MPa. Approximately 5 g of crushed sample was used for each measurement."

Jan 1, 2016

By R. L. Derick

The Orchard Valley Mine, a large underground coal mine located in western Colorado, experienced a major mine fire during an idled Sunday on June 1, 1986. This mine had extensive problems with spontaneous combustion near the coal outcrop. Spontaneous combustion has been determined to be the probable cause of that fire. Preparing for a mine emergency was an on-going task. Once the emergency occurred, much of the preparation work was implemented and aided in controlling the situation. Later, the successes and shortfalls that arose from that emergency were analyzed for future course of action. This paper summarizes the activity that led up to the major fire, the handling of that emergency, the lessons learned, and the changes implemented.

Jan 1, 1993

By J. S. Stachulak

The Diesel Emissions Evaluation Program (DEEP), a research consortium formed in 1997 by Canadian mining companies, labour unions, and provincial and federal government departments, completed its work by mid-2006. This program, in which Vale Inco participated with both direct funding and in-kind contributions, investigated the ability of currently available technology to significantly reduce underground concentrations of diesel particulate matter (DPM) with high efficiency and low maintenance over a long-term period (years of life).While DEEP?s testing showed that engine maintenance is a critical component for lowering DPM, it was clear that reduction of DPM to the very low target levels of ~0.05 mg/m3 was not possible with maintenance alone. The best candidate technology for achieving low DPM levels was particulate filter systems. Furthermore, successful deployment of such systems was highly dependent on removing them from having to rely on human intervention for their regeneration. The search continues within Vale Inco to identify a reliable and rugged system.

Jan 1, 2009

By Edward A. Vitunac

The emerging importance of pneumatic conveying systems for bulk materials is becoming recognized by more persons responsible for materials management as consultants, at the corporate level and at the plant level. They have learned that the economic advantages of a pneumatic system are frequently decisive when compared to alternate methods. Included in these advantages are relative simplicity, ease of installation, flexibility, ease of maintenance, cleanliness, safety and ease of automation to the degree desired. In general, installed costs favor a pneumatic system when compared to competing mechanical systems if the transporting distances are long or to and from many points. In addition, supplemental use such as cooling, heating, or drying may supply the incremental value required to justify its selection. (1). The main disadvantages of a pneumatic system is the greater horsepower required per unit weight of material conveyed and material limits in abrasiveness and density. In addition, there is a tendency to increase material breakage at changes of direction and at any obstruction such as the imperfect butting of one, piece of pipe to another in the conveying line. Classification of the material at the discharge may also cause problems in dusting and segregation. Materials weighing less than 4 pounds per cubic foot tend to cause feeding and collecting problems although they can be conveyed easily. Material between 4 and 20 pounds per cubic foot can be handled with less problems but flow rate is hard to predict. The 20 to 60 pounds per cubic foot range offers best results; whereas, over 60 pounds per cubic foot, materials tend to drop out of the air stream and settle in the pipe line unless careful provisions are made to prevent it. (2).

Jan 1, 1967

By D. E. Traut

A fluidized countercurrent ion-exchange system was developed, operated, and evaluated by the Bureau of Mines. The system consisted of integrated multiple-compartment absorption and elution columns in which the solution flows are continuous except for short periods when resin increments are withdrawn. The exchange of uranyl sulfate between a simulated acid leach uranium solution and a strong-base, ion-exchange resin together with the subsequent elution with an acidified sodium chloride solution was studied. The effects of the number of sections, section heights, amount of resin withdrawal, and solution flow rates were investigated. Also examined were the kinetic and equilibrium relationships for the absorption step. The experimental data indicate a strong interdependence between variables. Solution retention time appears to be a major limiting variable. The column was efficient over a range of conditions, but close control was needed for optimum operation.

Jan 1, 1975

By T. B. Szwilski, R. D. Begley

Status of ISO 14000 standards. The ISO 14000 are voluntary international standards providing a frame-work that allows a company to integrate an effective environmental-management system (EMS) into its operations. The purpose of an EMS is to provide a systematic procedure to identify the environmental aspects of a company's activities, evaluate any significant impacts and use the information to set objectives and targets toward continuous improvement of the company's environmental compliance and performance. In addition to the specifications for certification, ISO 14000 can be used as a guide to develop an effective environmental-management system or for self-declaration. The International Organization for Standardization (ISO) is a worldwide federation founded in 1947 to promote the development of international manufacturing, trade and communication standards. The organization is now represented in 118 countries, with the American National Standards Institute (ANSI) representing the United States. The principal goals of the ISO is "to promote the development of standardization and related ac¬tivities in the world with a view toward facilitating the international exchange of goods and services and to develop cooperation in the sphere of intellectual, scientific, technological and economic activity." ISO develops standards with input from government and industry. Because the standards are voluntary, there are no legal requirements to pressure countries to adopt them. However, many governments, industries and US agencies are adopting the ISO standards as a requirement for business trans¬actions, thereby, compelling suppliers to adopt ISO standards. These business and market forces, which are likely to be strategic business issues in the 21st century global marketplace, are imposing the need to develop a systematic approach to environmental management. The ISO 14000 series evolved from a United Nations Conference on the Human Environment in 1972. It includes a broad range of elements: the basic environmental management system, environmental auditing criteria for internal and external auditors, criteria for environmental performance evaluation (EPE), environmental labeling criteria and life-cycle assessment methodologies. The standards comprise two categories: organization evaluation standards and product oriented standards (Table 1). The ISO 14001 specifications contain the requirements for developing an environmental-management system that may be objectively audited for certification. The ISO 14004 standard provides guidance on interpreting the ISO 14000 specifications for the development and implementation of the EMS and for coordination with the management system of the company. On Sept. 1, 1996, the American National Standards Institute (ANSI) and the Registrar Accreditation Board (RAB) signed a formal agreement to create a new entity called the National Accreditation Program (NAP). To obtain certification, a company must fulfill the requirements outlined in ISO 14001. It is required that "a third party give written assurance that a company's EMS meets all the requirements of ISO 14001." Preparing for ISO 14000 can include subscribing to voluntary environmental initiatives; learning from ISO 9000 quality-management experiences; and utilizing information from recognized training courses, publications and numerous Internet resources. Once committed to an EMS, the management should provide sufficient resources to achieve continuous environmental-performance improvement, as outlined in an environmental policy. A thorny issue now being debated concerns the potential liabilities of documenting the environmental performance of a company. General impact of the ISO 14000 EMS standards. With increasing stakeholder awareness, costly end-of-pipe pollution-control approaches and the success of ISO 9000 quality-management standards, the ISO 14000 EMS standards are being adopted by companies and governments worldwide. The United States and Canada have well-established programs. In Europe, countries differ but are firmly committed toward environmental-management standards (BS 7750, EMAS and ISO 14000). The Department of Environmental Protec¬tion of the State of Pennsylvania is using ISO 14000 as a vehicle to develop a closer working relationship with industry, and it is anticipated that this policy will eventually lead to fewer environmental site inspections for those companies with ISO 14001 certification. The Depart-

Jan 1, 1999

By Dominique Francois-Bongarcon

The world mining industry is facing a severe recession. Thus, it is time to recall the value of geostatistical methods which were formerly developed as a money-saving and productivity-increasing tool. The situation has worsened, but the techniques of geostatistics have dramatically changed. Up to millions of dollars can be saved during exploration with simple use of variograms; then, during reserves estimation with kriging methods; and finally, with the parameterization of reserves, when evaluating a project and optimizing its global mining parameters.

Jan 1, 1983

By D. A. Baker, E. A. Gyawu, K. Awuah-Offei

Several underground coal mining disasters, such as Upper Big Branch in 2010, have revealed technological and organizational shortcomings related to self-escape. Efforts to address these gaps have primarily been top-down, that is, identified and implemented by upper management or external governing bodies. In contrast, this study employs a novel miner-centered approach to identify perceived technological boundaries to self-escape. Using a semi-structured, scenario-based survey, we elicit direct feedback from miners about current, emerging, and hypothetical technologies aimed at improving self-escape during mine emergencies. The results show a general high usefulness rating across all 21 technologies in the survey. Miners who work underground (both outby and working face miners) appear to give higher usefulness ratings overall than miners on the surface and other locations. This work will be directly applied to a series of proof of concept and prototype studies on self-contained self-rescuers (SCSRs), refuge alternatives (RA), and communication devises aimed at improving self-escape technologies through miner-centered research and design.

Mar 2, 2022

By Armine F. Banfield

Selection of a plant site is becoming increasingly more difficult and important, mainly due to advances in technology, antipollution laws and changing economic, social and community conditions. Discussion falls naturally under three headings: economic considerations, terrain considerations and environmental considerations. Aside from acquisition of surface rights, problems having to do with terrain, or topography, usually can be dealt with by management alone. Economic considerations largely involve decision-making by management plus negotiations with government regulatory agencies acting under set rules. Environmental considerations, such as air and water pollution, townsites, housing, schools, noise abatement, appearance, surface rehabilitation and the like usually are under the control of federal, state or municipal bodies with a large degree of decision-making. Successful solution of environmental problems often requires lengthy negotiations, during which public relations by the mining company play an important part. Existing union regulations or customs may confine decision- making and the establishment of wage rates, working conditions and regulations. These usually require considerable planning and negotiation. Initial production often is delayed by formal negotiations involving environmental considerations. Surface facilities usually can be divided into two broad categories: those for concentrating ores--such as gold, silver, base metals, low-grade iron ore and potash-which should be close to the mine to reduce ore-transportation costs to a minimum, and those where the ore is shipped elsewhere for treatment, such as direct-shipping iron ores, complex high-value ores requiring specialized treatment and ores from which special products are derived for local markets. The long-term aspects of plant-site selection too often are given no or insufficient consideration because of immediate financial limitations. As a result, additional capital expenditures may be required later for relocation of townsites, roads, railroads and plants to provide additional room for extension of open-pit operations, tailings disposal, storage, or danger to foundations through underground subsidence or open-pit mining. In the past, hillside sites for concentrating plants were preferred to take advantage of gravity-feed methods The modern trend, however, is to place as much equipment as possible on approximately the same level. Some costs relating to plant sites are included in this section. They are ranges as of the year 1970, and are offered only as general guides. Such costs will vary widely with geographical location and, of course, are subject to escalation due to increases in wage rates and cost of materials. Items in the bibliography contain more detailed and comprehensive data on specific subjects. Most contain bibliographies of their own.

Jan 1, 1973

By Joel Lööw, Jan Johansson, Erik Lund

Digitalization and automation technology offer new possibilities to increase productivity and obtain higher levels of autonomy in mining operations. Introducing autonomous systems into mining is not only a technical problem in terms of effectiveness and efficiency, nor a problem of safety in human-automation interactions. The systems also need to be designed and developed so that they foster healthy and attractiveworking environments. The design and development phase of newmining technology has not been extensively studied previously. To fill this knowledge gap, we investigated technology developers’ basic assumptions about humans and their interactions with the technology they develop. We conducted five semi-structured workshops within an EU funded project concerned with developing digitalization and automation solutions for the mining industry. The data suggests that many critical functions will still be under human control in future mining systems. The results also indicate increased complexity in the interaction between autonomous systems and humans as the technology becomes more advanced. As a result, we suggest that a human perspective, based on sociotechnical principles, should not only be considered in implementing the technology at mines but also in the early conceptual phases of developing and designing the technology. This will ensure healthy and attractive work environments in the future mining industry.

Mar 26, 2024

By Arthur W. T. Grimley

Hydraulic coal mining is being successfully practiced in China, U.S.S.R., Japan and Canada and in each country, excepting Japan where suitable sites are not available, the system is being expanded to either existing conventional mines or new mines. Productivity levels and economics at these mines are in all cases better than the productivities achieved in conventional mines in the same general localities. In the U.S.S.R. face productivities approaching 50 tons per man shift have been reported while in Canada the latest statistics show average face area productivity levels are in the region of 200 tons per man shift production monitor. In the United States hydraulic mining has not been actively pursued to the same degree and consequently there are no full scale hydraulic coal mines in operation or construction. Because many of the coal measures in the Western U.S.A. are generally somewhat similar to those being successfully hydraulic mined in Western Canada and parts of Siberia it is realistic to believe that successful hydraulic mines can be designed and developed in the Western U.S.A. Particularly if the vast technological base that already exists is used to improve on other people's ideas, systems, methods and equipment.

Jan 1, 1983

By W. A. Crosby

The ability of open pit mines to steepen overall final wall angles allows significant cost reductions as a result of reduced waste movement requirements. Final wall angles are principally controlled by three factors: geological conditions; hydrological conditions; and wall control blasting practices. The first of these factors is not controllable by the mine operator, the second can be influenced to some degree, but the last one certainly can be controlled, hence the current interest in final wall blasting practice at many mining companies. This paper discusses common blasting techniques employed to steepen final pit walls and outlines the attractiveness of moving from small hole high cost systems to the use of full size production drills as a means of reducing wall control blast costs. Attempts to make this change have been limited at many mines by the physical size of the drills and their inability to reverse drill. In the past, pres pi it, pre-shear or trim holes have had to be drilled vertically, at considerable distance from the upper bench toe, with the result that inter-berm face stability is reduced and final wall angles have to be made somewhat more shallow than desirable. The paper concludes with a description of how these problems can be overcome by utilizing the new Bucyrus 39R which has the capability of drilling at a ?15 degree angle underneath the machine. It is concluded that the resulting wall control blast designs will offer large mines improved final wall angles with resulting significant overall cost reductions.

Jan 1, 1998

By CORNELIUS STEPHANUS LODEWYK SCHUTTE, WIEHAN ADRIAAN PELSER, JEAN HERMAN VAN LAAR, MICHAEL DAVID HARMSE

Rising electricity costs in South Africa have resulted in a need for optimized compressed-air networks in the mining environment. As a result, the financial benefit of air receivers needs to be reconsidered along with the economic dispatch strategy. This study investigates the use of an evolutionary algorithm in the mining industry to determine the potential financial benefit for various-sized air receivers, as well as their dispatch strategy. A genetic algorithm was selected due to the improved solution reliability and accuracy compared to other optimization techniques. This study indicates that a genetic algorithm can be used to determine the optimal dispatch of compressed air in the deep-level mining industry. Further, this study indicates that air receivers are financially viable in the mining industry and can be used to reduce operating costs, improving profitability.

Dec 1, 2022

By M. J. Laurila

The concentration of low grade iron ores to pellets or sinter fines suitable for blast furnace feed or direct reduction is highly energy intensive and costly in terns of both size reduction and separatory processes. Large equipment with high throughputs are required to make the fine grinds and multi-stage separations economical. Control of these circuits is essential to producing a high grade product. As a result, iron ore concentrators possess some of the more sophisticated instrumentation for process control in the mineral dressing industry. These instruments must characterize flowstreams of up to 8,000 gpm where 80% of the particles are less than 50 µm. The past decade has been one where enormous strides have been made in automated control of iron ore plants. This paper reviews state-of- the-art control systems for crushing, grinding, magnetic separation, froth flotation and sizing/classifying circuits. Trends toward computerization and plant automation in response to a dismal outlook for North American steel production are also examined.

Jan 1, 1984

By H. Sahay

The current Canadian coal production is approximately 57x106 tonnes per annum of which some 25 million tonnes is exported. Two thirds of the Canadian output is classified as thermal and one third as coking or metallurgical coal. The Canadian coal industry, like the industries in some other industrialized nations, has gone through a cycle of ups and downs. The current world vide recession and stable oil prices have somewhat dampened the plans for a further growth of this industry - albeit temporarily. No new mines are expected to be developed within the next few years. However the production is projected to increase to 60x106 tonnes in 1985 increasing to an estimated 75 to 80x106 tonnes by 1995. The Canadian mines are highly mechanized and are willing to employ the modern technology to maintain its competitive position in the world's coal market. This paper reviews the recent technical developments which continue to improve resource recovery and productivity.

Jan 1, 1986

By Richard L. Ash

Usually stresses generated by explosive charges during blasting are considered to propagate through materials in a spherical manner. Although conical stress-waves had been suggested by a few investigators they have never been clearly defined or critically observed. An experimental technique using models and lengths of Mild Detonating Fuse was developed to produce conical stress-waves and study their effects. Several materials with different properties were tested to compare the influence of those properties on wave shape and crater formation. The investigations showed that whenever column charges were end-initiated, conical stress-forms were produced if the explosive's velocity exceeded the energy propagation velocity of the surrounding material. The stress-cone angle significantly affected fragment size and shape as well as the geometry of craters produced.

Jan 1, 1967

By A. J. S. Spearing, A. Mueller

The support of intersections in coal mines remains an important safety issue, mainly because the large diagonal span compromises the stability of the roof. This structural weakness is further exacerbated if the intersection is developed incorrectly, the pillar corners fail or the crosscuts are angled (not perpendicular). This report details the current support systems used and investigates unplanned falls of ground in intersections in coal mines throughout the United States. A possible failure mechanism is proposed and some suggestions are made to improve the effectiveness of the support in these vital areas.

Jan 1, 2009