AMENDED CERTIFICATE of APPROVAL Goldcorp Canada Ltd
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CONTENT COPY OF ORIGINAL Ministry of the Environment Ministère de l’Environnement AMENDED CERTIFICATE OF APPROVAL INDUSTRIAL SEWAGE WORKS NUMBER 7853-7RHPUM Issue Date: September 22, 2009 Goldcorp Canada Ltd. Musselwhite Mine Post Office Box, No. 7500 Thunder Bay, Ontario P7B 6S8 Site Location: Musselwhite Mine - Patricia Mining District Unsurveyed Territory (Kenora Area Office) Unorganized Area, District of Kenora You have applied in accordance with Section 53 of the Ontario Water Resources Act for approval of: establishment of sewage works for the collection, transmission, treatment and disposal of mill slurry water, surface runoff, mine dewatering, and sanitary sewage, serving a gold mining and mill complex processing gold ore using the carbon-in- pulp (CIP) gold recovery process, located at Opapimiskan Lake, approximately 130 km north of Pickle Lake, as follows: Proposed Works A. TAILINGS MANAGEMENT AREA (TMA) Tailings Impoundment Area A Discharge Dyke for the thickened tailings up to elevation 312 m along the northwest, west and southwest boundaries of the TMA to facilitate initial thickened tailings deposition. Proposed increase to the storage capacity of the TMA from 17.3 to 32 million tonnes. This is to be achieved by implementing a thickened tailings disposal system together with a de-sulphurized process, which will render the tailings non-acid generating. Deposition Strategy The tailings will be stacked and a vegetative cover provided for closure. The tailings pond will be partially drained. The overall tailings deposition strategy is described in Golder (2009a) and summarized below: Partition TMA with a Separation Dyke to maintain a clear water pond downstream of the dyke for water management purposes Construct starter Discharge Dyke to elevation 312 m on competent ground on west end of TMA and commence thickened tailings deposition from the dyke in 2010. Convey excess thickener overflow to the tailings pond via ditches downstream of the Discharge Dyke. Continue tailings deposition from the west end of the TMA. Raise and extend the Discharge Dyke as required. Maximum elevation of the Discharge Dyke is 328 m. Maintain an overall slope of about 4:1 on the downstream slope of the Discharge Dyke for closure. Dispose of the sulphide concentrate from the flotation plant in dedicated cells within the TMA maintaining the concentrate in a saturated state at all times. Cover the concentrate cells with tailings at closure Desulphurization System The proposed flotation and thickening plants are designed to remove sulphides and pyrite from the cyanide (CN) destruction reactor tailings stream to prevent acid generation extending the life of the TMA by creating layered non- sulphide tailings at higher deposition angles and by removing the sulphides in the flotation process. The system also includes a groundwater interception system to capture plumes of dissolved sulphate and other contaminants originating CONTENT COPY OF ORIGINAL from the TMA migrating towards Zeemel Lake. The system consists of: Flotation Plant A new conditioning tank to mix water from the flotation concentrate thickener overflow with: potassium amylxanthate (PAX) and copper sulphate at variable dosages (the reagent system), to be pumped to the flotation cells. Two (2) new Outotec 100 m³ flotation cells (or approved equivalent) in series to receive the conditioned tailings feed from the conditioning tank, all housed in a new flotation building. The flotation system is equipped with blowers and a pump box, from where the flotation concentrate is to be pumped to the flotation concentrate thickener. A new 12 m diameter insulated high-rate thickener tank to thicken the flotation concentrate tailings for deposition in the TMA. The thickener system underflow will be pumped approximately 1.1 km south to the TMA for deposition under the water cover to prevent acid generation. The overflow will flow by gravity to the flotation process water tank for reuse as dilution water. A new containment curb one metre high to be built around the perimeter of the flotation foundation for potential leak containment. A new reagent generation system located in the flotation building to manage three reagents PAX, Methyl Isobutyl Carbonol (MIBC) and copper sulphate. The reagent room is designed with containment for leaks, fire protection system and explosion proof walls. Thickening Plant A new tailings thickening process consisting of 16 m diameter high compression thickener located adjacent to the thickener plant (2.7 km west of the flotation building), equipped with a flocculant system and assorted pumps. The thickening plant will thicken the desulphurized tailings from the flotation process and distribute it into the TMA at a higher solid density than the current slurry deposition. Storage of sulphide concentrate tailings in containment cells within the existing TMA during operations, and below the water table at closure. A deposition system to the TMA, by means of centrifugal pumps located around the perimeter of the TMA over a distance of approximately 1 km, with flow split in two directions along the north and south sides of the TMA. A pipeline system consisting of three (3) new exterior pipelines with spigots to allow the de-sulphurized tailings to be deposited at various locations and in layers to increase tailings storage in the TMA. The new pipelines and existing pipeline include: 1. Thickened tailings pipeline. This will be a 200 mm diameter HDPE with a 254 psi rating pipeline. It has approximately 1,000 m length from the flotation tailings thickener around the dam at the TMA, where it will be spigotted to stack the tailings. 2. Flotation concentrate underflow pipeline. The approximate length is 2,500 m from the flotation concentrate thickener to the TMA. The pipeline will be 4" diameter HDPE insulated and rated for 100 psi, and will be monitored for leaks by differential flow meters, with a bypass line to deposit flow in the TMA in case of leaks. 3. Excess water pipeline. This will be a 200 mm diameter HDPE insulated pipe rated 100 psi, with approximately 1,000 m length from the flotation tailings process water tank to the reclaim barge. 4. Existing tailings pipeline. This extends from the mill to the TMA, and will be tied into the flotation tailings pump box in the new flotation building and discharge into the flotation tailings thickener at the new thickener building at the TMA. A ditch system consisting of two (2) ditches as follows: Ditch extensions to carry the thickener overflow to the tailings pond, with approximate 750 m length in the south ditch and 600 m in the north ditch. Groundwater Interception System Seven (7) pumping wells equipped with throttling valve for flow control at the well head and flow meters will be located along the access road between the TMA and Zeemel Lake as noted in the GW Interception System Report (WMC, 2009). The designations for these wells will be 09PW-3 to 09PW-9, located as per Figure #1, prepared by Schlumberger Water Services, dated September 11, 2009 (Version 1). A collection point in the form of a sump, equipped with a pumping system to convey the groundwater from this collection point to the TMA, or the seepage collection pond for temporary storage. Ten (10) piezometers to monitor the groundwater level and the well efficiency and the interception system performance at the following locations, as per Figure #1, prepared by Schlumberger Water Services, dated September 11, 2009 (Version 1): 1. five (5) piezometers between the new pumping wells (designated as 09GW-31 to 35); 2. two (2) piezometers at either end of the line of pumping wells (designated as 00GW-19, which already exists, and 3. CONTENT COPY OF ORIGINAL 1. 2. 09GW-36); and 3. three (3) piezometers between the pumping wells and Zeemel Lake (designated as 09-GW-37 to 39). A flow metering device installed in the collection point for flow rate monitoring. Existing Works A. TAILINGS MANAGEMENT AREA (TMA) Counter-Current Wash for Cyanide Recovery Tailings from the CIP circuit to be washed in two (2) counter-current thickeners each of 10.6 m diameter for the recovery of cyanide from the tailings, to be reused in the gold recovery process. Inco S02/Air Treatment Plant One (1) INCO SO2/Air type treatment plant for the treatment of tailings slurry for the destruction of cyanide and precipitation of heavy metals and iron, the treatment system designed to destroy 12.4 kg weak-acid dissociable cyanide (CNWAD) per hour from the Musselwhite tailings slurry stream of 245 m³ per hour having a maximum solids content of 50% by weight solids, designed to achieve a final residual cyanide concentration in the treated effluent of less than 1.5 mg/L CNWAD, having the following process parameters: a single continuous stirred tank reactor (CSTR) with agitator and down comer, the tank measuring 8.5 m in diameter and 9.0 metres in height, with an operating volumetric capacity of 475 m³; sulphur dioxide to be introduced into the bottom of the CSTR by means of a liquid sulphur dioxide dosing/storage and delivery system; with treatment plant air compressor, liquid oxygen enhancement, and tank agitator sized to provide a minimum dissolved oxygen concentration in the reactor of 4 mg/L; dissolved copper sulphate catalyst to be added as required to maintain a dissolved Cu2+ concentration of 5 mg/L, or zinc sulphate to be added as required to maintain a dissolved Zn2+ concentration of 7 mg/L; using an appropriate mixing and delivery system; slaked like obtained from the plant lime system to be added to the CSTR system to maintain the optimum operating pH in the reactor (at approximately pH 8.0 to 8.5); with provision (if required) for an automated process control system for the remote monitoring and control of the INCO SO2/Air Treatment System, with treated tailings slurry effluent from the CSTR to flow to the tailings distributor.