2015-03-24_HYDROLOGY - P2014019

• Permit No: P2014019
• IBM Index Class Name: HYDROLOGY
• Doc Date: 3/24/2015
• Doc Name: Discharge Permint Determination
• From: CDPHE
• To: DRMS
• Email Name: MAC
• Media Type: D
• Archive: No

3/24/2015 State.co.us Executive Branch Mail -Notice of Intent to Conduct Prospecting Application; Hock Hocking Mine; File No. P- 2014019
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Notice of Intent to Conduct Prospecting Application; Hock Hocking Mine; File
No. P- 2014 -019
1 message
Rosow - CDPHE, Kathleen <kathleen.rosow @state.co.us> Tue, Mar 24, 2015 at 3:27 PM
To: Michael Cunningham - DNR < michaela .cunningham @state.co.us >, Greg Lewicki <greg @lewicki.biz>
Michael,
This communication is in response to your February 13, 2015 memo to Eric Oppelt, in which you summarize
the exploratory mining activities proposed by Hock Hocking Mineral Company LLC for the Hock Hocking Mine
(Notice of Intent to Conduct Prospecting Application - File No. P- 2014 -019). At issue is whether the Water
Quality Control Division will require a discharge permit for the proposed prospecting activities. The
information provided by the applicant (Adequacy Responses - January 12, 2015 and February 6, 2015)
indicates that the proposed activities will likely impact the existing discharge from the mine, which
subsequently discharges to Mosquito Creek. Exploratory activities that impact water quality trigger
CDPS individual discharge permit coverage. Further, any land disturbing activities associated with
the proposed prospecting activities trigger industrial stormwater permit coverage.
Division policy WQP -5, Permit Policy for Mining Activities (attached) discusses when a
CDPS individual discharge permit is required for exploratory mining activities. WQP -5 indicates that a permit
is required if the activity impacts water quality - the example provided is a mine with a historic drainage that
is entered for exploratory purposes. The policy also provides an example of an exploratory activity that does
not trigger a permit requirement, in which all exploration is accomplished by core drilling from the surface,
without entry into the mine. The proposed exploratory activities at the Hock Hocking Mine clearly align with
the former, not latter, example.
Information provided by the applicant indicates the potential for the proposed exploratory mining activities to
impact water quality (e.g., quantity of drilling water to be used [4 -6 gpm]; use of a anionic
polyacrylamide polymer in the drill fluid; the applicant's presumption that water will be encountered in the
drill holes). Importantly, the applicant proposed using straw wattles (sediment control logs) as a control
measure for the drill fluid /drill hole water, and indicated that this water will pass through the wattles and
enter the existing mine discharge, which subsequently discharges to Mosquito Creek:
`The water leaving the waddles will be inspected every 30 -60 minutes during the drilling operation. If
any water leaving the waddles shows any sign of sediment, additional waddles will be placed. If for
any reason the sediment level in the water leaving the drill site cannot be made to be clear, the
operation will shut down immediately until a solution can be found.'
Note that a Preliminary Effluent Limitations (PEL) document was prepared for the Hock Hocking Mine, and
was submitted to the division by Greg Lewicki and Associates. A PEL is a fee -based service, typically prepared
by the division, which identifies the preliminary (anticipated) effluent limitations for a discharge to state
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