REP45988

• Permit No: C1981041
• IBM Index Class Name: Report
• Doc Name: 1994 Annual Hydrology Report & Mine Inflows Study
• Annual Report Year: 1994
• Permit Index Doc Type: HYDROLOGY REPORT
• Media Type: D
• Archive: No

POWDERHORN COAL COMPANY
1994 ANNUAL HYDROLOGIC REPORT
AND MINE INFLOWS STUDY
OCTOBER 1, 1993 THROUGH SEPTEMBER 30, 1994
Introduction
During the 1994 Water Year, the Year, the names of the Roadside and
Cameo No. 1 mines were changed to the Roadside South Portal and the
Roadside North Portal respectively. Production of coal continued
to be primarily from the Roadside South during this Year. A small
amount of coal was mine from the Roadside North in May 1994 and
since the end of this reporting period the focus of mining has
changed to the Roadside North due to a thicker seam and higher
quality.
The management role of Peabody Western Coal Company in Flagstaff,
Arizona, was reduced during the Year but their environmental
department continued to provide assistance for hydrologic
reporting. The delay in preparation of this report was partially
due to delays in programming changes that were made by Flagstaff in
the hydrologic reporting system to make it a mine site PC based
• system. The general format of this report is the same as in
previous years. Some of the numerous tables and graphs that were
prepared for the 1993 AHR have not been repeated due to their lack
of significant information. Lowess and Trilinear diagrams are
again used in this report.
Changes in the monitoring and reporting during the Year include the
addition of outfall 015 to our CDPS permit, the elimination of
Chronic Whole Effluent Tests from our discharge monitoring
requirements, the addition of 30 new piezometers on the Cameo
Refuse Disposal Area No. 1, commitment to quarterly water level
monitoring at the Unit Train Loadout piezometers , annual full
suite analysis of two piezometers at the Unit Train Loadout, and
the addition of quarterly monitoring of the water level in old
portions of the Roadside South.
There was error in getting sample bottles in time for full suite
samples in September 1994 and as a result water quality information
taken on October 3, 1994 was included in this report.
Surface Water
Water flow and quality on the Colorado River is monitored by the
U.S. Geologic Survey (USGS) at various locations. The closest
location is Station No. 09095500 which is located upstream
approximately 7 miles north east of the mine site. Water quality
and flow from this site are used as a general representation of the
Colorado River upgradient of our mining operation. There is a
diversion to the Government Highline Canal, the addition of Plateau