Geology Reference
In-Depth Information
Figure 16.2.2. Map of anthracite coalfields in Pennsylvania. From Chaiken et al. (1983, p.3)
strip pits on the southern edge of the fire to reduce the amount of oxygen entering the mine. It would also include
exploratory drilling on the northern, eastern, and western edges to delineate the boundary of the fire. A temporary
flushed noncombustible barrier would be emplaced to constrain the fire while the second phase of the control
project was completed. Phase II consisted of excavating a permanent isolation trench on the cold side of the
flushed barrier. The depth of the trench was estimated at between 30.1 and 61.0m (100
-
200 ft). Phase I was
completed, but exploratory drilling indicated that the
fire had advanced further
than anticipated. Phase II would
now require an isolation
(300 ft) deep. As the first part of Phase II, an underground barrier
west of the fire would be constructed from the outcrop to the mine pool by injecting fly ash into the mine voids. In
1973, an underground flushed barrier was installed, but due to the depth, cost, and the amount of surface disruption
trench more than 19.4 m
Table 16.2.2
Number, average cost (US$1000), and estimated success rate (%) of US bureau of mines fire-control projects
in the anthracite fields between 1949 and 1978.
Method
Number of projects
Estimated effectiveness (%)
Average cost (US$1000)
Excavation
10
80
26 581
Flushing
14
43
5306
Surface Seal
2
50
41
Source
: Data from Chaiken et al. (1983).
