Surface mining explosives

These values can be compared with the effects of mining explosives. The amount of rock (hard limestone rock) demolished in an open air mine is of the order of 7-10 t per kilogram explosive (Colombo, 1997). The rock in our example corresponds (in ideal conditions) to about 20 kg of explosive, an amount considered to be modest. The effect of an airplane crash, then, may cause, according to the usual assumptions, an impact load of about 10000 t on a surface area of 7m, corresponding to about 150 kg cm . This load might cause the fall and the... 

Most mines in the United States are surface mines that do not pose risks of catastrophic explosions or fires. Virtually all mines, however, present some risks that are unique to mining. At the same time, they pose a wide variety of risks akin to those in other heavy industries. AH of these risks come within the purview of MSHA. 

Whereas an explosion from methane tends to be localized, it may start coal dust explosions resulting in more widespread injury and loss of life. AH coal breaking operations result in formation of fine coal particles some are controlled with water during the mining operation. Breakage associated with hauling disperses dust, and dust accumulations can be made safe by rockdusting. Powdered limestone is spread over the mine surfaces to cover the dust. 

Oil Shale Oil shale is nonporous rock containing organic kero-gen. Raw shale oil is extracted from mined rock by pyrolysis in a surface retort, or in situ by steam injection after breaking up the rock with explosives. Pyrolysis cracks the kerogen, yielding raw shale oil... 

Explosions can occur in coal mines when coal dust, with a very large surface area, reacts with oxygen in the air without heating. Lumps of coal, with a smaller surface area than coal dust, do not react with oxygen unless heat energy is supplied. 

U.S. Army CRRDC also measured surface contamination. In addition, they measured flux of molecules from mines in both air and water. Mines form one of the larger groups of explosive bearing targets for trace chemical sensors. Therefore, these measurements provide some insight into the concentrations at the source... 

This concentration in puddles does not require a buried source. If a source on, or above, the surface receives rain, concentrating puddles can form. Since the presumed reason for searching for trace explosive molecules is to locate the source, some ingenuity may need to be exercised to complete that task. In fact, Phelan and Webb [1, pp. 70, 71] report on work by Hewitt et al. [16] where they buried mines on a gentle slope. The signatures from these mines were found to form in patterns where concentration decreased with distance (a few feet) from the mine as the surface water flowed down the slope away from the mine. 

Editor In Chapter 4 of this book we examine the issue of leakage of explosive from mines. We attribute a comment to you about the resulting pattern of dispersal of the explosive molecules on the ground surface. Of course, the details of the local topography have a dominant effect, but you indicated that in nearly flat areas you routinely notice a peculiar pattern. Please address this issue. 

Type 3 Mark 1 Aircraft Mine Model 1 was cylinder 53 inches long and 24 inches diam, provided with a parachute and four chemical horns. It was filled with 240 lbs of Type 98 Explosive.. The detonator and booster were located in a tube running transversely thru the mine case. It was dropped from an aircraft or surface moored (p 42, Figs 11 12)... 

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