PERMFILE64784

• Permit No: M1977004
• IBM Index Class Name: Permit File
• Doc Date: 9/8/1983
• Doc Name: Internal Memo
• From: DMG
• Media Type: D
• Archive: No

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R¢har~ D. Lamm
Governor
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FROM:
RE:
DEPARTMENT OF NATURAi R~~~l.1B.CES ,~
David H. Getches, Exec -~
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DAVID C. SHELTON, Director Class: czl2. ~ v Type-Seq.:
From: (~ f-t ~ To:
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Doc. Date (if no date stamp): q-~_g ~ p~
September 8, 1983
Mark Loye _ `,\C\
Jim Pendleton ~'
Homestake's ch ject's
Our visit to Fbmestake's Pitch
experience. I can only regret
while at the site. My doctor'
contracted the day before at o
estaolishments. As a result of
for your consideration.
fVorth Overburden Pile
~eotechnical Considerations
Project on September 1 was a fascinating
the unfortunate deterioration of my health
s diagnosis currently favors food poisoning
ne of Capitol Hill's finer eating
our visit, I forward the following comments
Tne northern overburden pile has experienced a moderately large deoris flow.
The deoris deposit can be observed to extend in excess of 100 feet downslope
from the original pile's toe, reaching a maximum thickness of approximately
15 feet. The operator's representatives postulated that the flow resulted
from the deposition of viscous muck from the northern pit on too steep a slope
gradient, which appears plausible. The operator's representatives briefly
showed us an analysis and a design graphics for remedy of the situation,
proposing a terraced remedial treatment for the pile face. The toe drain has
already been extended in order to prevent blockage. The operator is
proceeding towards a remedy in a prudent mangler. I will schedule a review of
their analysis and the design suggestions upon its subgnittal.
Final Drainage Cross-Ditch
The operator proposes a final ditch frogn the south pit's lake outfall to tale
area immediately oelow the toe of the north overburden pile, as a component of
the final abandonment configuration for the Pitch Project. We expressed
concern for this relatively impermanent geomorphic facility during our last
roeeiing with the cognpany's representatives. I am particularly concerned about
the potential effects of a flood event larger than the ditch's design
capacity, originally presented as 200 years at our earlier meeting. The flow
of spillage from the ditch during such an event could potentiatiy relocate the
preferred flow route fur the ditch, resultiny in unacceptable levels of
erosion and sediment generation.
423 Centennial Building, 1313 Sherman Street Denver, Colorado 80203 Tel. [phone]