Minimizing subsidence effects during production of coal in situ
First Claim
1. A method of limiting the ground surface effects of subsidence draw on surface facilities used in the production of coal in situ, comprising the steps ofestablishing the outer and inner limits of a barrier pillar within the perimeter of the project area, thendigging a subsidence draw protective trench within the periphery of the inner limits of the barrier pillar to a depth corresponding to the lowermost portion of the foundations for structures located within the barrier pillar area, with the resultant providing a discontinuity in the surface rock.
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Accused Products
Abstract
Coal is reduced to ash in place by gasification using in situ production techniques, resulting in significant void space underground, which in turn causes roof fall and subsidence. Overburden collapse is stabilized by backfilling with foaming mud cement that hardens into an expanded solid, which quenches and fills the production module and seals residual ash. Rubble volumes and subsidence cracks are sealed against water incursions and contaminated water excursions. Surface facilities above barrier pillars are protected from destructive forces of subsidence draw.
58 Citations
2 Claims
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1. A method of limiting the ground surface effects of subsidence draw on surface facilities used in the production of coal in situ, comprising the steps of
establishing the outer and inner limits of a barrier pillar within the perimeter of the project area, then digging a subsidence draw protective trench within the periphery of the inner limits of the barrier pillar to a depth corresponding to the lowermost portion of the foundations for structures located within the barrier pillar area, with the resultant providing a discontinuity in the surface rock.
Specification
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- Resources
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Current AssigneeGreg H. Thompson, Page T. Jenkins
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Original AssigneeSite Technologies Incorporated
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InventorsVaseen, Vesper A., Stoddard, Xerxes T., Stoddord, Xerxes T.
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Primary Examiner(s)Taylor, Dennis L.
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Application NumberUS06/488,065Time in Patent Office477 DaysField of Search405/258, 405/288, 405/259, 299/11, 299/19US Class Current405/288CPC Class CodesE21B 33/138 Plastering the borehole wal...E21B 43/247 in association with fractur...E21F 15/00 Methods or devices for plac...
