Page 197 - Advances In Productive, Safe, and Responsible Coal Mining

176 Advances in Productive, Safe, and Responsible Coal Mining

3. The costs of quality impacts from OSD extraction were estimated at $5.09 and $1.26 per ton
of mined roof and floor strata, respectively. Including all other factors (mining, processing,
waste disposal, etc.), OSD costs were estimated to be $13.51 and $9.28 per ton of ROM
material. The difference between roof and floor costs suggests that if out-of-seam extraction
is required for height or any other reason, floor should be mined instead of roof.
4. The total combined cost impact of OSD was estimated at $3.95 per ton of clean coal.
Accepting the fact that OSD cannot be entirely limited, even a 50% reduction becomes a
worthy target that if achieved would result in a cost savings of $2.00 per ton.
Having established the need for and value of reducing OSD extraction, two control
strategies were presented. The first and easiest to implement is an educational aware-
ness program (EAP). EAPs target operational OSD, that is, that caused by production
practices that limit visibility or that result from the common assumption that
processing eliminates it from the final cleaned product. An effective EAP requires
detailed analysis of existing conditions and practices in order to establish benchmarks
and targets that emphasize economic impacts. Given accurate information, most mine
workers will respond with conscientious efforts to minimize OSD extraction; how-
ever, the mining environment is very dynamic, and it is easy to lose focus when break-
downs and other operational issues halt production altogether. Thus, refresher EAPs
should be conducted on a frequent (e.g., quarterly) basis.
The second strategy is technology-based, and it targets OSD caused by engineering
designs that include the use of larger, heavier equipment. Larger equipment requires
increased mining clearances often necessitating the extraction of some OSD. Heavier
equipment damages weak floor strata that become mixed with loose coal during
cleanup operations. Numerous technologies have been developed and tested with
the most successful being some form of coal interface detection (CID). CID systems
use radiation (gamma, infrared, Doppler, etc.), vibration, energy, or force to detect
coal seam boundaries and guide mining machine operators in avoidance of those
boundaries.
The message of this chapter is that OSD control is of vital importance. Effective
strides have been made in understanding causes and impacts of OSD, but these have
been on a macro level; whereas to be effective in controlling OSD, this understanding
needs to occur at or be transferred to the micro level within companies and at individ-
ual mines. One way to do this is by integrating OSD analysis into permitting activities,
which seems to have usurped the attention of most mining engineers. Associating
OSD control with permit applications can satisfy both regulators focused on
minimizing environmental impacts of waste disposal and mine operators focused
on minimizing production costs. Efforts in both directions will enhance the compet-
itiveness of the coal industry and improve the marketability of coal as a low cost and
clean burning fuel of choice.

Acknowledgment

Support for multiple research studies summarized and cited in this chapter was provided by the
Illinois Department of Commerce and Economic Opportunity through funding administered by
the Illinois Clean Coal Institute.