REP09032

• Permit No: C1981038
• IBM Index Class Name: Report
• Doc Date: 7/23/1993
• Doc Name: 1992 ANNUAL SUBSIDENCE REPORT
• Permit Index Doc Type: SUBSIDENCE REPORT
• Media Type: D
• Archive: No

through July 1984. Surveys were wnduc:ted again in Novenber,
• 1987, and January, 1992. Station 8 overlies approximately
~I 1000 feet of overburden. 'Ihe station showed no consistesit

15I~o !~ indication of subsidence effects through 1987. 1992 survey
P~,,.~/ I~"` results show an elevation gain of 0.35 feet evident since the
last survey (1987). Reference to Permit No. C-81-038, Map No.
2-2 shows that station 8 lies in the general vicinity of a
large mapped landslide area. An evident change in no*'thi TMm
aryl Basting coordinate positions may be indicative of natural
landslide movement. The II West Submains were advanced in the
vicinity of station 8 during October, 1990. The 1st North, 2
1/2 West area approximately 500 feet southwest of station 8
was retreat mined fran May through June, 1983. Mining
activity took place north of station 8 during 1992 in Panel
A+.
Station 14: Station 14 is located in the Stevens Gulch alluvium protective
buffer zone over approximately 750 feet of overburden. The
R~ AaB;~a~a station was initially surveyed in June, 1982. subsequent
l surveys were conducted annually since 1988. Data indicates
the station has seen an overall increase in elevation
totalling 1.07 feet. Panel G was advanced under this station
on September, 1988. Retreat mining occurred outside the
Ir-~ ~~'°'"~~ buffer zone in the vicinity of this site in February, 1989.
a~ Panel C was advanced adjacent to this site in December, 1992.
1^0- v,„J~ a5 An elevation adjustment of -0.55 feet was detected at this
• U" Y`/ site in October, 1989 but was perhaps influenced by control
ef~yy~' station coordinates being redefined. January 1991 data
indicated 0.31 feet were subsequently gained but again, new
control point coordinates were generated. January 1992 data
indicates 0.01 feet of elevation was lost over the last year.
No mining activity took place in the vicinity of station 14
during 1992 prior to the subsidence survey.
Station 15: Station 15 was newly established for the 1991 surveying year.
Q Station 15 overlies approximately 700 feet of overburden and
~~.D is located within the 600 - 800 foot overburden depth Stevens
~y, ~%~~ Gulch alluvium protective buffer zone. Panel B was retreat
mined with partial floor extraction during May, 1992 in the
immediate vicinity of station 15. 1992 data indicates no
elevation change at this station as compared to last year.
Station 16: ~ Station 16 overlies approximately 950 feet of overburden.
Surveys at station 16 were initiated in August, 1982 and
r, ~1(I~,Qi continued biannually through 1984. Annual surveys occurred in
U" ' ~ January and September, 1992. The 1st North, 3 West panel
/,,,, A U" ~ adjacent to and east of station 16 was retreat mined in
~Y~ October, 1981. Panel A, located beneath station 16 was
retreat mined in July and August, 1991. 1992 survey data
indicates a 0.09 feet elevation gain at this site. Station 16
is located within a mapped landslide area as well and sane
• minor coordinate variability has been recorded.
Station 88: Station 88 lies south of and adjacent to the II West Submain