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| | Going Underground — Part One |
 | | Other regulations unique to underground mines include telephone systems situated near each working section in most areas of the mine, other communications systems that may be used in an emergency, canopies on mobile equipment to protect operators from falling material, and — where appropriate — shaft and hoisting procedures, and methane monitoring systems. |
 | | When deciding whether to go underground, several inherent properties and characteristics of the seam should be considered such as overburden strength or potential to serve as a strong roof support, water quantity and quality that may be encountered, geologic anomalies, previous mining activities, utility lines, buildings, roads, structures, and property issues, among several other considerations. |
 | | The third type of underground mine, the drift mine, is the least complex of the three because this system may be used when the rock to be mined is close to the surface — or where it outcrops. |
| www.aggman.com /articles/jan05a.htm (3169 words) |
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