Yellowknife Gold Project

The Yellowknife Gold Project (YGP) mine plan is based on mining two deposits (Ormsby and Nicholas Lake) with a feed to a single mill at the Ormsby property. Both deposits will be mined initially by open pit (approximately 3 years) followed by underground operations developed from the bottom of the pits.  The YGP will process approximately 857,000 to 1,225,000 tonnes per year of ore. This will give a milling rate of 2,500 tonnes per day (TPD) to a maximum of 4,000 TPD. The water license application is based on the maximum production rate of 4,000 TPD.  It is currently estimated that approximately 15 million tonnes of waste rock will be produced at the Ormsby deposit and approximately three million tonnes will be produced at the Nicholas Lake deposit. All waste rock not used as construction material will be stored in engineered waste rock storage areas with seepage collection systems. At the Ormsby deposit the seepage from the waste rock storage area will be directed to the Tailings Containment Area or the mill process. At Nicholas Lake the seepage will be treated if necessary and then released to the receiving environment. Only non-acid generating waste will be used as construction materials.  The expected mine life for the YGP will be dependent on final mill throughput, however; at a production rate of 2,500 TPD, mine life would be ~ 13 years and at a production rate of 4,000 TPD, mine life would be ~ 8 years.

Site preparation will consist of upgrading the access roads within the property to all weather roads with culverts installed where appropriate. Additional roads will be constructed to the waste disposal area(s), process plant site and explosives magazines.  The estimated quantities of sand and gravel are 75,000 to 100,000 tonnes for buildings, roads and associated structures. The estimated sand and gravel requirements for the tailings containment area at Winter Lake are approximately 25,000 tonnes and, 15,000 tonnes of clay type material, respectively.

The proposed plant process flow sheet incorporates conventional crushing and grinding.  Slurry from the grinding circuit will pass through a gravity concentrator to recover the free gold. Cyclone overflow slurry will then be fed to the flotation circuit to recover native gold and associated sulphide minerals to the flotation concentrate. The gold in the flotation concentrate will be leached and recovered in a conventional carbon-in-leach circuit using dilute cyanide solution. Activated carbon adsorbs the dissolved gold and is recovered by screening. The gold is eluted from carbon conventional carbon stripping technology and recovered by electrowinning onto steel fibre cathodes. The stripped carbon will be regenerated and returned to the carbon-in-leach circuit to recover more gold.  The slurry from the cyanide leach circuit will be treated using the Caro’s Acid or Inco SO2/Air process to detoxify the remaining cyanide. The treated cyanide leach slurry will be added to the uncontaminated flotation tailings and pumped by pipeline to Winter Lake, the proposed tailings containment area. Gold recovered from both the gravity and leach circuits will be smelted on site and shipped as Dore bars for refining.

The proposed and preferred location for tailings disposal is Winter Lake. Reclaim water will be optimized from Winter Lake. This area has an estimated storage capacity of approximately 7.9 million cubic metres (13.4 million tonnes). The quantity of tailings that are expected to be produced over the mine life is 12 million tonnes.  All process tailings will be deposited into Winter Lake. All dams constructed at Winter Lake will be impermeable structures. All process tailings will be pumped and initially deposited sub-aqueous into Winter Lake and as the mine matures, sub-aerial tailings deposition may be implemented. Reclaim water will be optimized from Winter Lake and pumped back to the process plant. During the feasibility study and detailed design phases, tailings management strategies will be developed further and included in the projects’ overall Environmental Management System (EMS) which will be part of projects’ final Developers Assessment Report (DAR).

Developers Assessment Report (DAR)

Developers Assessment Report (DAR)

Tyhee Gold Corp. All rights reserved.
Last updated November 12, 2011