2017-04-14_REPORT - M1977004

• Permit No: M1977004
• IBM Index Class Name: REPORT
• Doc Date: 4/14/2017
• Doc Name: Annual Fee/Report/Map
• From: Barrick Gold
• To: DRMS
• Annual Report Year: 2017
• Email Name: DMC
• Media Type: D
• Archive: No

Pitch Reclamation Project Colorado Mined Land Reclamation Board—2016 Annual Reclamation Report
The field-scale pilot testing conducted in 2016 included the following specific activities:
• Required regulatory approvals/authorizations were obtained prior to initiating the pilot testing,
including the following:
o United Stated Environmental Protection Agency(USEPA) Class V Underground Injection
Control (UIC)"authorization by rule"was received on May 5, 2016(No. C050000-11148),
which was required to demonstrate that injection of reagents into the underground workings
would not impact underground sources of drinking water.
o A chemical usage authorization was received from the WQCD on June 3, 2016,which
allowed reagents to be used during pilot testing that were not directly specified by the
CDPS permit(No. C00022756).
o TR-7 to the reclamation permit No. M-1977-004,with a focus on surface disturbance during
piezometer completion and required restoration,was approved on May 9, 2016.
• Four new piezometers (RD-01, RD-02, RD-03, and RD-04)were installed at the foot of the Indian
Rock Dump to support water recirculation, reagent dosing, and downgradient monitoring.
• New and existing piezometers were used to extract and reinject a total of 150,000 gallons of
water(75,000 gallons in each of the P-4/P-11 and P-5/P-12 areas)from the underground mine
workings dosed with a mixture of phosphoric acid and sodium monophosphate, and non-reactive
dye tracers fluorescein and Rhodamine WT. The phosphate reagents were injected with the goal
of reducing uranium concentrations in the underground workings by precipitating dissolved
uranium within calcium phosphate minerals. The tracer was added to aid in the pilot test
performance assessment and further understand groundwater flow rates and directions within
underground workings.
• A similar phosphate injection pilot test was conducted in the Indian Rock Dump,which involved
the extraction and reinjection of 25,000 gallons of water,with dosing of a mixture of phosphoric
acid, sodium monophosphate, sodium tripolyphosphate, and the nonreactive dye tracer eosine.
The objectives of these tests were similar to the tests performed in the underground mine
workings, but with the further goal of evaluating rock dump-specific hydrological and geochemical.
conditions.
• ETC reactive media, including zero valent iron, fish bone apatite, and peat soil (to achieve
bioreduction)were tested in 55-gallon drums and PVC columns receiving flow from Tie Camp
drainage.
• Implementation of a treatment residuals management system along Indian drainage above the
Sediment Control Pond for the treatment of residual phosphate in the event that phosphate was
measured in surface water. The treatment residuals management system involves dosing of iron-
and aluminum-based reagents for precipitation and removal of phosphate.Although phosphate
was not observed in surface water in 2016, a dry-run of a treatment residuals management
dosing system was tested on Indian drainage,which involved the direct dosing of ferric chloride in
to the drainage. Bench tests were also performed to evaluate phosphate removal efficiency with
the iron and aluminum reagents.
The 2016 field work was successful in demonstrating the effectiveness of the phosphate injections and in
obtaining information necessary for larger-scale advancement. Specifically:
• In-situ phosphate-based injections are effective in reducing uranium concentrations within and
immediately downgradient of the injection zones.
• Injected phosphate is observed to attenuate in the injection zone, and phosphate was not
observed above the analytical detection limit of 0.1 mg/L as total phosphorus in surface water in
2015 or 2016.
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