Based on differences in the permittivity of coal and limestone rock, a resonant cavity measurement technique is presented for the rapid determination of the proportions of coal and limestone in powdered mixtures. The ratio of the resonant frequency shift and the change in the transmission factor when mixed coal and limestone samples are inserted into the cavity provides a means for estimating t...

To improve the coal permeability and outburst prevention, coal seam water injection and a series of outburst prevention measures were tested in outburst coal mines. These methods have become important technologies used for coal and gas outburst prevention and control by increasing the external moisture of coal or decreasing the stress of coal seam and changing the coal pore structure and gas de...

An area of major concern in considering increased coal production and utilization is the health and safety of increased numbers of workers who mine, process, or utilize coal. Hazards related to mining activities in the past have been especially serious, resulting in many mine related accidental deaths, disabling injuries, and disability and death from chronic lung disease. Underground coal mine...

The Outburst can be defined as a sudden release of coal and rock accompanied by large quantities of gas into the underground coal mine workings which represents a major hazard in underground coal mines. Gas drainage has been proven to be successful in reducing outburst hazards by decreasing the in-situ gas pressure. One of aspect of gas drainage from coal seams is coal matrix volume changes. Cu...

BACKGROUND The present study was conducted to investigate the probable changes in blood pressure of workers in coal mines. METHODS In this study 91 workers, who worked in forwarding, preparation and exploitation units of coal mines and were in direct contact with carbon dioxide gas (from fireworks), have been selected as the case group, and 70 workers, who did not have direct contact with thi...

At the northern tip of Colombia, Jonathan Bloch hunts for fossils in the midst of spontaneous combustion fires, noxious gases laced with foul-smelling sulfur, rock-shattering explosions, and some of the largest machines in the world. “It is a weird place to work,” Bloch admits, an associate curator of vertebrate paleontology at the FloridaMuseum of Natural History, although he says he feels saf...

Recent NIOSH published information has shown an increase of rapidly progressive coal workers’ pneumoconiosis (CWP) in the southern Appalachian coal region (SAR) of the U.S., despite the fact that compliance data indicates that most coal miners have been exposed to coal mine dust concentrations below the statutory limit of 2.0 mg/m3. While the exact cause of these elevated CWP levels in the SAR ...

This study investigates the risky positioning behaviour of underground coal mine employees, specifically the behaviour of drivers of remote controlled continuous miners. The patterns of behaviour of these employees are of particular interest, not only because of a series of fatal accidents in New South Wales coal mines with such equipment, but also because of the lack of scientific enquiry of r...

in advance longwall mining, the safety of mine network, production rate, and consequently, economic conditions of a mine are dependent on the stability conditions of gate roadways. the gate roadway stability is a function of two important factors: 1) characteristics of the excavation damaged zone (edz) above the gate roadway and 2) loading effect due to the caving zone (cz) above the longwall w...

Knowledge of in situ stresses is fundamental to many studies in earth sciences, and coal mine ground control is no exception. During the past 20 years, it has become clear that horizontal stress is a critical factor affecting roof stability in underground coal mines. The theory of plate tectonics and the World Stress Map (WSM) project has been extremely helpful in explaining the sources and the...