Pretium Resources building Brucejack gold reserves
The Brucejack Project is northwest British Columbia. Source: Pretium Resources Inc.
Pretium Resources Inc. [PVG-TSX, NYSE] reported a positive updated Valley of the Kings mineral reserve estimate for its Brucejack Project in northwest British Columbia, where construction and development continues on schedule for commissioning of the underground mine in mid-2017. The company also reports the appointment of Robert Quartermain to Executive Chair and Joseph Ovsenek as President and CEO effective January 1, 2017.
Highlights of the updated Mineral Reserve estimate include:
- Proven mineral reserves in the Valley of the Kings increased to 1.6 million ounces gold (3.3 million tonnes grading 14.5 g/t gold) which is sufficient for the first three years of mine life.
- Proven and probable reserves in the Valley of the Kings increased to 8.1 million ounces gold (15.6 million tonnes grading 16.1 g/t gold).
Areas of gain in the reserves are attributed to the following factors:
- Increasing drill density to 7.5- to 10-metre centers allowed for conversion of a significant amount of probable reserve to the proven reserve category. Mining stopes within the existing reserve model along with expansion of the previous indicated resource wire frame accounted for an increase of approximately 620,000 ounces of gold.
- Several new, adjacent stopes were added to the previous mine plan as a result of the infill drilling reaching beyond the previously defined ore. This expansion to the mine plan accounts for an increase of approximately 300,000 ounces of gold.
- Adjustments were made to the stope orientation and design parameters, along with the addition of grade to the background mineralization for the estimate which had previously been modeled at zero grade. Estimating waste blocks within the stopes with the July 2016 Mineral Resource estimate grade accounts for an increase of approximately 200,000 ounces of gold.
The updated reserve estimate is based on the July 2016 resource estimate for the Valley of the Kings. The July 2016 resource estimate was updated based on the 2015-2016 Valley of the Kings infill drill program which consisted of 63,740 metres in 367 drillholes designed to target stope areas to be mined in the first three years of the current mine plan (1320-metre level to 1200-metre level). Table 1 below is a summary of the updated Valley of the Kings Mineral Reserve estimate.
Table 1: Valley of the Kings Mineral Reserve Estimate – December 2016
| Category | Tonnes (millions) |
Gold (g/t) |
Silver (g/t) |
Contained | ||||||
| Gold (million oz) |
Silver (million oz) |
|||||||||
| Proven | 3.3 | 14.5 | 12.9 | 1.6 | 1.4 | |||||
| Probable | 12.3 | 16.5 | 11.3 | 6.5 | 4.5 | |||||
| Total | 15.6 | 16.1 | 11.1 | 8.1 | 5.9 | |||||
Construction and development continues on schedule for commissioning of the underground mine in mid-2017.
Following the full enclosure of the mill building in October, internal construction has progressed significantly. Over 45% of the internal structural steel is now complete and concrete continues to be poured and is over 80% complete. Concrete is currently being poured in the gold recovery area and the truck drive through bay.
All major equipment continues to be delivered according to schedule including the flotation concentrator which is now on site. Flotation tanks and tailings thickener are being assembled and the process and fire water tanks have been installed. The SAG and ball mills sole plates are now in place and grouted and ready for mill shells installation. SAG mill bearing housings have been installed. Transformers have been installed within the mill. Electrical and mechanical contractors are now on site, and electric and piping installation has been initiated in the mill and underground.
The 330-person camp which includes mine dry, offices, recreation facilities, dining hall and kitchen is substantially complete and fully operational.
The transmission line construction continues to progress towards completion. All of the towers are in place and the first 42 km of the 57-km transmission line is now energized to the Knipple substation. The first of the three wire conductors of the final 15 km have been strung and the second is approximately 60% strung. The transmission line is expected to be fully energized early next year, ahead of when it is required for mine commissioning. An additional six diesel generators have been delivered to site and three of the six generators are fully commissioned. The generators will provide more than adequate power to maintain full mill and underground production in the event of any transmission line failure.
The main portal access for the Valley of the Kings has broken through to surface and the steel structure of the portal building is under construction. The portal will serve as the primary access point to convey the gold ore from the underground crusher to the mill.
Underground development remains on schedule and crews are advancing at an average rate of over 30 meters per day. Excavation of the major infrastructure is now complete including the crusher and transfer area. The third and final vent raise has broken through to surface. Underground work is focused on continued ramp and level development with seven mining stopes now accessible. Concrete and slab installation for the underground crusher and transfer tower continue to progress. Approximately 30,000 tonnes of ore has been stockpiled in preparation for mill commissioning expected to start in mid-2017.