Okvau Gold Deposit

Emerald announced on 1 May 2017 the completion of the Definitive Feasibility Study (DFS) on the development of a 2.0Mtpa operation at its 100% owned Okvau Gold Project located in the Mondulkiri province of eastern Cambodia. The DFS was completed to +/-15% level of accuracy.

On 26 November 2019, Emerald critically examined and pursued improvements in all aspects of the Okvau Gold Project economics applied to the May 2017 DFS. Based on the prevailing gold price at the time of US$1,450/oz. and updating the key assumptions and inputs, the NPV (5%) of the Okvau Gold Project significantly improved to US$337M (A$488M) pre-tax and US$238M (A$345M) post-tax with an outstanding Internal Rate of Return (IRR) of 69% pre-tax and 57% post-tax.

In summary, the DFS demonstrates high grade, low cost, compelling development economics:-

  • Initial Ore Reserve of 14.3Mt @ 2.0g/t Au for 907,000oz at an average AISC of US$754/oz over an initial 7 year Life-of-Mine (‘LOM’) operating period;
  • 2.0Mtpa plant to produce approximately 106,000oz pa on average over the initial operating LOM of over 7 years;
  • Mineral Resource estimate of 17.7Mt @ 2.0g/t gold for 1.14Moz  (at 0.7g/t cut-off) with 1.01Moz as Indicated and 0.13Moz as Inferred;
  • Single open pit with waste:ore ratio of 5.8:1;
  • Using US$1,450/oz Au gold price:
  • NPV(5%) US$337M pre-tax and US$238M post-tax;
  • IRR 69% pre-tax and 57% post-tax;
  • Payback ~1.4 years pre-tax and 1.7 years post-tax.

The DFS confirmed the robust nature of the Project with an initial operating LOM of over 7 years, producing approximately 106,000 ounces of gold per annum on average from a single open pit, with ore processed through a plant utilising a single stage crushing circuit and SAG mill, sulphide flotation, regrind mill followed by conventional cyanide leaching. 

 Okvau Grade Control Simulation

Emerald has embarked on a simulated grade control drilling program to further de-risk the development of the Okvau Gold Project. The results to date continue to strongly support the DFS Ore Reserve estimate in the area tested, particularly in respect to gold grade and add strongly to the company’s confidence in its ability to reconcile reserve grade and ounces (during operations) with the intended mining equipment type, scale of operation and grade control methodology. The cost of the program are expected to represent an operating cost saving.

The key aspects of the program are as follows;

  • Infill Grade Control simulation drilling programme 368 holes for 10,100m;
  • 10m x 10m infill pattern to an average vertical depth of 25m;
  • Results confirm continuity, grade and tonnage estimate of resource model.

Image 1

Selected results of the simulated grade control drilling include:-

  • 4m @ 22.93g/t gold from 18m (GC0688)¹;
  • 3m @ 26.36g/t gold from 19m (GC0239)²;
  • 2m @ 39.35g/t gold from 13m (GC0877)³;
  • 16m @ 4.30g/t gold from 8m to eoh (GC0871);
  • 5m @ 13.65g/t gold from 20m (GC0344).
  • 18m @ 3.68g/t gold from 12m (GC0240)².
  • 6m @ 10.35g/t gold from 12m (GC0199)¹;
  • 8m @ 7.59g/t gold from 16m (GC0200)¹;
  • 3m @ 20.14g/t gold from 18m (GC0307);
  • 12m @ 4.78g/t gold from 6m (GC0305);
  • 6m @ 9.32g/t gold from 23m to eoh (GC0698);
  • 5m @ 10.48g/t gold from 14m (GC0277)²;
  • 10m @ 13.92g/t gold from 13m (GC0930)³Ä;
  • 20m @ 6.84g/t gold from 5m to eoh (GC0872)Ä;
  • 11m @ 11.70g/t gold from 19m to eoh (GC0732)²Ä.


Ä +100gm intersections.

1 Refer ASX release dated 27 December 2017.

2 Refer ASX release dated 10 January 2018.

3 Refer ASX release dated 3 October 2018.

4 Refer ASX release dated 24 October 2018.


Okvau Resource Growth - Expanded Open Cut and Underground Potential

The Company is drilling to test interpreted feeder and extension zones which have the potential to add to the existing resource and positively impact on the economics of the Okvau Gold Project.

Selected Okvau feeder zone intersections:-

  • 15m @ 11.92g/t from 143m (RC19OKV390)²,³Ä;
  • 8m @ 19.98g/t from 172m (RC19OKV397)²,³Ä;
  • 16.9m @ 10.87g/t from 78m (DD16MET003)¹Ä;
  • 9m @ 13.23g/t from 47m (DD11OKV073)¹Ä.


Ä +100gm intersections.

1 Refer ASX release dated 4 April 2019.

2 Refer ASX release dated 2 July 2019.

3 Refer ASX release dated 31 July 2019.

Image 2

Some of the highest grade intersections sit beneath open pit floor including:-

  • 11m @ 8.4g/t from 390m (DD11OKV091);
  • 10m @ 9.6g/t from 411m (DD12OKV108);
  • 11m @ 8.4g/t from 399m (DD11OKV091);
  • 6m @ 9.7g/t from 520m (DD16OKV373).

Image 3

Refer to the ASX release dated 1 May 2017 and Renaissance Minerals Limited ASX release dated 19 September 2012.