نتایج جستجو برای: tabas parvadeh coal mines
تعداد نتایج: 37591 فیلتر نتایج به سال:
Static electricity is one of the reasons for gas explosions in coal mines. When miners leave the narrow tunnel exit of a coal mine, the body voltage may increase by more than ten times with the body capacitance decreasing quickly to 1/10 of its original value, and the body electrostatic discharge (ESD) energy can increase greatly to become a dangerous gas ignition source. In this work, simulati...
As more easily mined deposits are depleted, the reserves are becoming more limited and less favorable. Deposits of coal or trona that are being longwall mined are deep and are getting deeper. Coal bursts and bumps frequently occur within development entries in longwall mining of deep mines due to high stresses. This paper presents a novel patented longwall mining layout “Longwall Mining with Sp...
In underground excavation, where the road-headers are employed, a precise prediction of the road-header performance has a vital role in the economy of the project. In this paper, a new model is developed for prediction of the road-header performance using the non-linear multivariate regression analysis. This model is able to estimate the instantaneous cutting rate (ICR) of roadheader based on r...
Although rates of pneumoconiosis in coal miners have declined substantially in the United States since the passage of the Federal Coal Mine Health and Safety Act of 1969, new cases continue to occur, including cases of rapidly progressive disease. In contrast, Australia’s underground coal mining industry has reported few new cases of pneumoconiosis for more than 20 years. Mortality from coal wo...
Coal is an important fossil fuel and will also be for the next decades [1]. The only way to achieve the challenges faced by the coal industry is to reduce production costs by improving productivity. Improvement of productivity has become an important goal for today’s coal industry in the race to increase price competitiveness. In recent years, underground mining method is becoming popular becau...
Few study has been carried out on the desorption rules of extreme-soft and outburst-prone coal in south of China, especially coal from Hunan Province of which the value of “f” is normally less than 0.2. Desorption experiments are conducted on the coal samples from Hongwei and Jiahe Mines in Hunan Province, and the following phenomena can be observed: the calculating mean error by t method and p...
Some of the most difficult coal mine roof in the United States can be found in the Illinois Basin. Factors contributing to the high roof fall rate include weak, moisture-sensitive roof rock; high horizontal stress; and limited longwall mining. The depth of cover ranges from 27 to 300 m (90 to 1,000 ft), and roof damage from horizontal stress can be severe. Moisture-sensitive roof rock, which co...
BACKGROUND The mortality experience over 22-24 years of 8,899 working coal miners initially medically examined in 1969-1971 at 31 U.S. coal mines was evaluated. METHODS A cohort life-table analysis was undertaken on underlying causes of death, and proportional hazards models were fitted to both underlying, and underlying and contributing causes of death. RESULTS Elevated mortality from nonv...
There are many sources trough which the soil get enriched and contaminated with REEs. The determination of REEs in environmental samples has been limited because of the lack of sensitive analytical techniques. Soil samples were collected from four sites including open cast coal mine, natural coal burning, coal washery and control in the coal field located in Dhanbad, India. Total concentrations...
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