Gascoyne Resources

Glenburgh Gold Project


The Glenburgh Project in the Gascoyne region of Western Australia has an Indicated and Inferred resource of 21.1Mt @1.5g/t Au for 1.0 million ounces of Au from several deposits.

Gascoyne Resources

Gascoyne Resources Ltd –Project Locations

The Company announced on August 5, 2013 positive preliminary findings from a 12 month Feasibility Study that concludes that the Glenburgh Gold Project can support a viable project. Key project details are summarised below:

  • Mining inventory 4.9Mt @2.0g/t Au for 316,000 ounces over 4+ years
  • Life of mine revenue of $448 million
  • Pre-tax operating surplus of $163 million
  • Cash operating costs (C1) of $909/oz
  • All in sustaining costs of $991/oz
  • Capital costs of $60.4 million
  • Working capital (pre-production) of $10 million
  • Underground mine development (yr 3) $15 million
  • Sustaining capital of $13.2 million
  • Annual throughput 1.2Mtpa, producing 73,000ozpa 

Project Description

The Glenburgh project is situated in the Southern Gascoyne Province of WA approximately 250km East of Carnarvon.

Glenburgh Tenements

Glenburgh project tenement location map

Regionally the project lies in the southern Gascoyne Province adjacent to the northwest margin of the Yilgarn Craton. Geologically the province has been described as the high-grade metamorphic core zone of the Early Proterozoic Capricorn Orogen. The region comprises granitoid intrusions, gneiss domes, metamorphosed sedimentary rocks and remobilised Archaean basement gneiss.

The project overlies an east-north-east trending sequence of highly metamorphosed Lower Proterozoic rocks comprising variably quartz-feldspar-biotite-garnet-magnetite gneiss, amphibolite, quartzite and calc-silicate. A prominent crustal scale north-east trending fault, the Deadman Fault, bisects the project area.

Glenburgh Reources

Glenburgh Geology and deposit locations

Gold mineralisation at Glenburgh was first detected by Helix Resources in 1994 from gold anomalism in regional stream sediment sampling and subsequent soil sampling which outlined a 20km long anomalous trend. Drilling principally by Helix and since 2010, Gascoyne Resources has discovered and extended a series of gold deposits with JORC Resources. Gold mineralisation at Glenburgh is somewhat enigmatic as a result of the high grade metamorphic host rocks; gold occurs in quartz- feldspar- biotite-garnet gneiss with a general observation of higher grades occurring in silica “flooded” zones.

Glenburgh Reources

Feasibility Study

Gascoyne Resources announced to the ASX on August 5, 2013 positive preliminary findings from the 12 month Feasibility Study completed for the proposed development of the Glenburgh Gold Project. The studies base case was revised following the recent substantial fall in gold price to contemplate a life of mine feed grade of ~2.0g/t gold and concluded that the project can support a viable development under a range of scenarios.

The study was completed by a number of independent consultants and investigated several options, based around a carbon leach (CIL) treatment facility, processing approximately 1.2Mtpa. The project includes a number of conceptual mill feed sources including eleven open pits at Glenburgh, a high grade open pit at the Egerton project (currently under option) and an underground development at the Zone 126 deposit at Glenburgh.

From these mill feed sources, a total mining inventory of 4.9Mt @2.0g/t Au for 316,000 ounces of gold was estimated. It should be noted that while ~70% of the mining inventory is in the Measured or Indicated Resource category (and could be converted into a Probable Reserve), 30% of the material in the mine plan is classified as Inferred and hence can't be converted into a reserve. As a result a reserve has not been calculated for the project and the financial assessments provided are preliminary in nature. There is no guarantee that furture drilling will result in the conversion of the Inferred Resource to Indicated allowing a reserve to be calculated.

Glenburgh Project – Potential Site Layout

The preliminary Feasibility Study has been managed and compiled by Gascoyne Resources, with input from a number of key external consultants including:

  • Drilling, assay collection & compilation: Gascoyne Resources
  • Resource modelling: RungePincockMinarco
  • Geotechnical logging & assessment: Dempers & Seymour
  • Glenburgh mining studies: Kenmore Mine Consulting
  • Egerton mining studies: Gascoyne Resources
  • Metallurgical tesk work: ALS AMMTEC
  • Metallurgical interpretation and design: Ashburton Hall Metallurgical Consulting
  • Processing cost estimate: Ashburton Hall Metallurgical Consulting
  • Flowsheet design: GR Engineering
  • Ground water: Rockwater
  • Tailings storage design: Coffey Mining
  • Environmental: Keith Lindbeck & Associates
  • Soil geotechnical assessment: Soil Water Group
  • Financial modelling & milling schedules: Gascoyne Resources

The study has identified a number of key areas that need to be refined prior to development. The main areas which need to be finalised are identifying and securing a suitable second hand processing facility and including the recent infill drilling into a resource update. The inclusion of the completed 2013 drilling program is expected to lead to an increase in the resource base, but more importantly conversion of a significant portion of the in pit Inferred Resource to the Indicated category. This is expected to allow an Ore Reserve to be calculated for the project.
Also on the critical path for the development of the project is finalising the native title negotiations. This will allow the grant of the mining lease, which is a pre-requisite for the permitting of the project.

Glenburgh Reources

Zone 126 Deposit – Long Section


There remains excellent potential to expand the existing resource base. A recent exploration outcome has been the delineation of a strong 5km long gold in soil geochemical anomaly NE of the known deposits.

NE Glenburgh – Gold Soil Anomalies

Within this strong gold trend extensive zones averaging >100ppb gold have been defined with individual samples grading up to 1.3g/t gold. These results have provided numerous resource growth targets which will be part of the company’s discovery drill program for 2013 and 2014.