REP01309

• Permit No: C1981038
• IBM Index Class Name: Report
• Doc Date: 12/11/2002
• Doc Name: 1993 ANNUAL SUBSIDENCE REPORT
• Permit Index Doc Type: SUBSIDENCE REPORT
• Media Type: D
• Archive: No

1993 survey data indicates an elevation gain of 0.25 feet.
• Station 6 is located within a mapped landslide area and may be
exhibiting movement associated with this feature. No mining
anticipated to produce subsidence has oociured in the vicinity
of Station 6 since 1983.
Station 14: Station 14 is located in the Stevens Gulch alluvium protective
buffer zone over approximately 750 feet of overburden. 'Ihe
station was initially surveyed in June, 1982. Subsequent
surveys were conducted annually since 1988. Data indicates
the station has seen an overall increase in elevation
totalling 0.21 feet. Panel G was advanced under this station
in Septenber, 1988. Retreat mining occurred outside the
buffer zone in the vicinity of this site in February, 1989.
An elevation adjustment of -0.55 feet was detected at this
site in October, 1989 but was perhaps influenced by control
station coordinates being redefined. January 1991 data
indicated 0.31 feet were subsequently gained but again, new
control point coorY3inates were generated. Panel C was
advanced adjacent to this site in December, 1992. Panel C was
partially retreat mined adjacent to this station during
February, 1993. October 1993 data indicates 0.86 feet of
elevation was lost relative to the 1992 survey.
Station 15: Station 15 was newly established for the 1991 surveying year.
• Station 15 overlies approximately 700 feet of overburden and
is located within the 600 - 800 foot overburden depth Stevens
Gulch alluvium protective buffer zone. Panel B was retreat
mined with partial floor extraction during May, 1992 in the
immediate vicinity of station 15. October 1993 data indicates
only a minor (0.06 feet) elevation change at this station as
cortg~ared to last year.
Station 16: Station 16 overlies approximately 950 feet of overburden.
Surveys at station 16 were initiated in August, 1982 and
continued biannually through 1984. Annual surveys occurred in
January and September, 1992, and October, 1993. the 1st
North, 3 West panel adjacent to and east of station 16 was
retreat mined in October, 1981. Panel A, located beneath
station 16 was retreat mined in July and August, 1991. 1993
survey data indicates a 0.18 feet elevation gain at this site.
Station 16 is located within a mapped landslide area as well
and some minor coordinate variability has been recorded.
Station DH 55: Drill hole 55 is located over the 1st West North panel with
approximately 1750 feet of cover. No minim had occurred in
the vicinity of Drill hole 55 as of the end of 1993. Zhe
collar elevation of DH 55 was originally established in 1981
at 8578.57 feet. Zhe monitoring point established at this
• site was surveyed in January 1994 at elevation 8543.11. An
apparent error in survey elevation data exists for this site.
Additional data will define current coordinates.
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