Old Pirate Gold Deposit
Overview
The Old Pirate Gold Deposit is part of the Twin Bonanza Mining project which is one of the key developmental projects for Prodigy Gold.
The Old Pirate Deposit is located on ML33459, 5.5km to the north-west of the Old Pirate Mine and 27km to the south of the Tanami Road.
Old Pirate hosts a total Mineral Resource (including Indicated and Inferred categories) of 0.76Mt @ 4.7g/t Au for 115Koz¹ using a lower cut-off grade of 1g/tAu.
This mineral resource estimation was completed in 2016 just after mining was suspended after producing 157Kt @ 5.9g/t for 29.3K ounces of gold sold² at the leased Coyote Mill. This mining was on top of trial mining that occurred at the project in 2013 which produced 8.1Kt @ 15.4g/t Au for 3.5Koz of gold sold³, this material was processed on site using a gravity plant.
Site infrastructure includes haul road, 8-person camp with workshop, office,kitchen facilities, fuel storage, gravity plant, water bore & airstrip.
¹ASX: 19 August 2016 ²ASX: 29 July 2016 ³ASX: 30 April 2014
Old Pirate Exploration History
The deposit was first recognised in outcropping veins in the late 1990s by North Flinders Mines.North Flinders, Normandy NFM and Newmont Asia Pacific all conducted exploratory work on the project with the last recorded drilling (prior to Prodigy) completed in 2005.
On 28 January 2010 Prodigy announced an offer to purchase a tenement package from Newmont Asia Pacific (Newmont) for a cash consideration of $10.775 Million, which included tenementEL23661. The acquisition was completed on 31 March 2010. In 2012 tenement EL23661 was split up and combined with other tenements and became EL28322 and EL28323. EL28322 (made up of part of EL23661 and EL22228) was granted on 3 January 2012 and hosted the Old Pirate Deposit.Prodigy Gold subsequently was granted a Mining Lease ML29822 covering the Old Pirate and Buccaneer Deposits which was subsequently split int ML29822 and ML33459, with ML33459hosting the Old Pirate Deposit.
During the financial year 2011/2012 Prodigy released surface trenching results from two fieldseasons, its JORC compliant maiden resource estimate, scoping study results and discoveries ofnew veins. In 2011 reverse circulation drill hole OPRC100021, testing the northern extensions ofthe system, intersected several zones of intense quartz veins in intercalated sandstones andshales, as well as a diorite intrusive body. The hole is located approximately 150m farther north ofthe main Old Pirate Prospect and intersected spectacular visible gold.
The Golden Hind Prospect was discovered in 2012 and was found to consists of severaloutcropping veins ranging from 3m to 30cm in width. The veins were mapped over a strike lengthof approximately 400m and continued under shallow cover to the northwest and southeast.
The development of four open pits, Western Limb, Old Pirate Central, Old Pirate South andGolden Hind, commenced at Old Pirate in late 2014/15. These four pits were designed to accessapproximately 150,000 tonnes of ore that would be mined and processed over a one-year period.
Old Pirate Mineral Resources
The Old Pirate Mineral Resource incorporates results from only the post 2010 RC and Diamond drilling completed by Prodigy Gold. This model used a top cut of 100g/t Au and a minimum wireframe width of 1m.
The Old Pirate Mineral Resource totals 760Kt at 4.7g/t Au for a total of 115koz of gold¹ and has been reported in the Indicated and Inferred categories.
The Old Pirate Mineral Resource was extended into the previously mined pits with the model then reconciled against the previous mining reported. While this material is not included in the reported resource, the 2016 model estimated 125Kt @ 6.6g/t Au for 26Koz compared to the reconciled mining of 149Kt @ 5.9g/t Au for 28Koz (difference to total production due to some material mined coming from outside of the reported resource around prospects like Old Glory).
¹ASX: 19 August 2016, ²ASX: 10 March 2023
Old Pirate Geology and Mineralisation
The Old Pirate Deposit is a coarse gold system that is hosted within bedded parallel quartz veins located in two regional-scale, southerly plunging anticlines. Quartz veins ranging from 20cm to 6m in width host the gold mineralisation. Gold can be very coarse with grains up to 5mm observed in hand-specimen. The mineralised quartz veins preferentially follow key shale horizons within the host turbidite package. The key shale horizons are generally thicker shales, with some up to 25m thick.
From mapping and limited diamond drilling, beds and mineralisation appear to be steeply dipping between 60o and 80o. The plunge of the high-grade zones is southerly at 20o.
At Golden Hind the mineralisation is 90m long and between 3 and 15m wide. Gold is hosted in quartz veins as well as ferruginous sheared sediments. In addition to steeply dipping structures there is also a shallow dipping geological feature that is not well defined.
For the 2016 Mineral Resource estimation, Old Pirate was split into several individual geological domains, each a part of the anticlinal structure, and each with its own geologic characteristics. The geology of each individual domain was used to guide the resource estimation for that domain.
Old Pirate Deposit Mining History
The Old Pirate Deposit has been mined using two different methods. The first was a trial mine that tested the higher-grade veins on surface with material processed on site using a standard gravity plant. The second was a more traditional truck and shovel method with ore transported to the then leased Coyote Processing Plant in Western Australia for traditional CIL processing.
Trial Mining¹ – Operation occurred during 2013-14. Mining small test-pits with material processed on site using a gravity plant. A total of 8,122 tonnes of material was mined and processed at a grade of 15.4g/t Au. Final reconciliated gold sold was 3,454 ounces with a gravity processing recovery of around 86%.
¹ASX: 29 July 2016 ²ASX: 30 April 2014
Traditional Mining² – Operation occurred during 2015-16. All material mined was transported from site to the leased Coyote plant in WA which was 80km away. Mining occurred at Old Pirate Western Limb, Central and South as well as Golden Hind. Minor mining was completed at Old Glory where around 1,000 ounces was produced.
Final production was 155,357 tonnes mined and processed at a grade of 5.9g/t Au. Final reconciled gold sold was 29,376 ounces with an overall processing recovery of 98.9%.