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Comparison of Aerial and Ground Surveying of Subsidence Over an Active Longwall.

Authors
Lascola-JC
Source
MISSING :12 pages
Link
NIOSHTIC No.
10006510
Abstract
The Bureau of Mines repeatedly surveyed a grid of monuments over an active longwall mine panel in southwestern Pennsylvania during a 1- yr period. Both conventional ground surveying techniques and photogrammetry were used. The objective of this investigation was to compare elevation measurements of subsidence obtained from aerial and ground survey methods under dynamic ground conditions. The results of a statistical analysis of the survey data show that the mean of the differences between 372 matched pairs of elevation measurments was 0.20 Ft (61 mm) with a 95-pct-confidence interval of 0.05 Ft (15 mm). The mean of the absolute values of the differences was 0.38 Ft (116 mm) with a 95-pct-confidence interval of 0.04 Ft (12 mm). Ninety-five percent of the absolute values of the differences were less than 1.11 Ft (338 mm).
Publication Date
19880101
Document Type
IH; Report of Investigations;
Fiscal Year
1988
NTIS Accession No.
NTIS Price
Identifying No.
RI 9214
NIOSH Division
PRC;
Source Name
MISSING
State
PA;
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