_REPORT - M1977448

• Permit No: M1977448
• IBM Index Class Name: Report
• Doc Name: BLACK HOLDINGS & PA
• From: BLM
• To: PETE KILBOURNE
• Media Type: D
• Archive: No

the residential area are contaminated is to test them. Even a finding of
radioactive materials in these waters would not indicate a specific source
.� because tpe uranium bearing Morrison Formation crops out along the entire length
of the canyon above the residential area.
Conclusions
Water emerging from the face-up (excavated outcrop) at the Little Don contains
dissolved radioactive substances, arsenic, atd selenium. Radioactive materials
_ are being eroded from the waste rock dump and ars probably moving offsite.
These contaminants are probably flowing into Twomile Creek and La Sal Creek may
ue infiltrating alluvium and bedrock in the near surface ground water
environment along the creeks. Near the bottom of the canyon, surface and near
r surface waters come in contact with the Entrada Sandstone. Once in ^!ontact,
these waters may infiltrate the Entrada and contribute to spring flow in the
residential area.
Any contamination of culinary springs in the Entrada Sandstone is probably
minimal for the following reasons: (1) The total amount of mine waters
entering the La Sal Creek Canyon hydrologic: system is minimal, approximately 5
gallons per minute. (2) The relatively greater natural flow from the creek and
springs tends to dilute any contaminants. (3) Most mine waters enter La Sal
Creek and continue flowing in the streambed past the residential area. (4)
Ground water movement of contaminants, from the mine site through permeable
strata, would be blocked by intervening fine grained strata. (5) Contact of
surface or near surface waters with the Entrada Sandstone acquifer at a level
that could intercept a spring would be over a short distance, approximately 1/4
mile. (5) The fine grained texture of the Entrada will make infiltration
slow.
BLACK HAT KIN ES
i
' The Black Hat Mines includes the Black Hat, Blue Cap, and St. Patricks mines.
Only the air vent area of the Black Hat Mine is on land administered by the
Manti-LaSal National Forest. The remainder of the Black Hat and all of the Blue
` Cap and St. Patricks mines are on land administered by the Bureau of Land
JManagement.
The Black Hat mines are located at the head of Lion Canyon a tributary of La
Sal Creek. The geology of the canyon controls ground and surface water pathways
that radioactive contaminants might follow. Lion Canyon flows southeast into La
Sal Creek which flows via Paradox Creek into the Dolores River. The State of
Utah has categorized the beneficial uses for La Sal Creek and its tributaries as
a cold water fishery (category 3a) and agricultural for irrigation and livestock
watering (category 4) .
The Black Hat Mine Complex exploits mineralized sandstone within the Salt Wash
Member of the Morrison Formation, The mines lies on the north limb of the
eastward plunging La Sal Creek Syncline. Beds in this area dip gently south.
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