APPCOR10060

• Permit No: C1981048
• IBM Index Class Name: Application Correspondence
• Doc Name: TECHNOLOGY OF AUGER MINING
• Media Type: D
• Archive: No

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These examples of highwall collapse are cited to indicate
that although the augering machine is located on the surface - that
this machine is also subject to the hazards of the highwall, and the
machine safety is contingent upon the operator's assessment and
evaluation of the geology and stability of the highwall. Too much
deviation in drilling operations or failing to. provide adequate
space between holes or in pillar support, lack of experience in
auyering, or his own zealous efforts to achieve as much coal as
possible can result in loss of machine.
Highwall spalling
Among the most prevalent hazards encountered in the auger
system, that of spalling off of the highwall of rock slabs or loose
material are among the most serious.
It was noted that at most mines visited, canopy protection _
for operators was not of sufficient strength to protect the auger
operators from spalling of any material. Most protection provided
consisted of only thin sections of steel, welded together with
screening material used for the canopy. -
Highwall Collapse
Similarly, no protection is provided for the operator in
case the highwall collapses and buries the machine.
Improvements in design are necessary to overcome these
potential problems. Only one auger that was visited had a full
length walkway with exits at the rear of the machine for an emer-
gency escapeway. This should be a mandatory design feature of all
augers since it provides an important protection in c~~~ of imminent
highwall failure by allowing the auger operators a fast means of
egress from the danger. _
Proper size and spacing of auger pillars and adequate
monitoring of highwall condition are critical to prevent a highwall
slide and consequent burial of the auger. During the course of
this study, it became apparent to the field teams that the spacing
of auger pillars by most auger operators was done by either rule-
of-thumb, or other inadequate criteria. Many operations leave
either 6-in. or 8-in. pillars regardless of whether a seam is 100
ft or 500 ft below the top of a mountain. Pillar spacing becomes
especially critical when a strip mine has left an island of over-
burden and coal because the economics do not justify further
stripping. The procedure many times is to auger completely around
the island, thus entirely undermining this mass of rock with the
exception of the small 6-in. and 8-in. pillar. If pillar spacing
is inadequate, the highwall will slide causing probable serious
injury to operators and effectively destroying the auger.