نتایج جستجو برای: underground mining
تعداد نتایج: 99723 فیلتر نتایج به سال:
Water has an important role in creating pollution problems in the mining regimes influencing the surrounding surface environment. The purpose of this study is to make an assessment of groundwater quality in an underground mine site in Portugal with a view of determining the pollution potential of groundwater. In the corresponding surface area of this underground mine, intersec...
The contamination of ores with wastes or materials of lower than the cut-off grade is referred to as dilution. Dilution is an undesirable phenomenon that, on one hand, reduces the product grade and, consequently, reduces the sales prices and, on the other hand, adds an extra cost to waste production. Therefore, studying and evaluating the dilution risk is important in mining, and especially in ...
Differential interferometric synthetic aperture radar (DInSAR) has been increasingly used to monitor ground surface deformations due to such occurrences as underground mining, fluid extraction, earthquake and volcanic activities. However, temporal decorrelation has made it difficult to derive useful information from a single pair of repeat-pass satellite radar images for vegetated regions when ...
The underground uranium mine Königstein (Saxony, Germany), currently in the process of remediation, represents an underground acid mine drainage (AMD) environment, that is, low pH conditions and high concentrations of heavy metals including uranium, in which eye-catching biofilm formations were observed. During active uranium mining from 1984 to 1990, technical leaching with sulphuric acid was ...
BACKGROUND Tanzania has a young mining history with several operating open pit and underground mines. No prevalence studies of noise-induced hearing loss (NIHL) have been conducted among mine workers to provide an impetus for the development of comprehensive hearing protection programmes. AIMS To determine the prevalence of NIHL and associated factors among miners in a major gold mining compa...
Natural Resources Canada (NRCan) is a federal government department specializing in the sustainable development and use of natural resources—energy, minerals and metals, forests—and in Earth sciences. NRCan deals with natural resource issues that are important to Canadians. These issues are examined from both a national and international perspective, our expertise in science and technology, pol...
Mine fill is the material placed underground to fill the voids created by mining excavations. It provides overall large scale ground stabilization while allowing localized pillar recovery. In addition to providing a working floor or back, mine fill has the potential to reduce subsidence and minimize dilution. Mine fill is essential to cut and fill, benching and sublevel stoping mining methods. ...
Labor productivity in U.S. coal mining increased at an average annual rate of slightly over four percent during the past 45 years. This report examines key factors contributing to that record particularly, technological innovation in both surface and underground mining and concurrent geographic shifts in U.S. coal production. Health, safety, and environmental regulations introduced in the sixti...
The longwall mining method is one of the most applied methods in extracting low-inclined to high-inclined coal seams. Selection of the most suitable extraction equipment is very important in the economical, safety, and productivity aspects of mining operations. There are a lot of parameters affecting the selection of an extraction equipment in mechanized longwall mining in steeply inclined coal...
Based on techniques of close upper protective coal-rock layer mining, relieved gas extraction, and underground gangue washing-discharging-backfilling, this paper initiates the concept of mixed fully-mechanized coal mining, which combines a solid backfilling method and a caving method (hereinafter referred to as “backfill and caving mixed mining”). After the principle and key techniques are intr...
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