Golden Deeps Limited (ASX:GED) has obtained higher gold grades after a re-analysis of rock samples from its Tuckers Hill Project, near Mudgee, NSW.
In December 2020, the Company completed reconnaissance geological mapping and rock sampling at the Tuckers Hill and Eldorado prospects north east of the Hargraves Goldfield.
41 rock chip samples were taken of quartz veins and mullock from historic workings returning a highest result of 9.64g/t Au from a quartz vein at Tuckers Hill.
Re-analysis of the samples using Intertek Laboratories ‘LeachWell’ method resulted in a highest grade of 15.61g/t Au from the sample that previously assayed 9.64g/t Au.
All rock samples that originally returned an assay value of greater than 0.1g/t Au returned a higher value with the subsequent LeachWell analysis. For example, a sample that previously assayed at 1.62g/t Au now re-assayed at 3.74g/t Au.
The higher gold values from the Leachwell analysis confirm the high gold grade of the quartz veins at Tuckers Hill and further justifies Golden Deeps’ planned diamond drilling program.
The gold at Tuckers Hill and the nearby Hargraves Goldfield has a ‘nuggety’ characteristic resulting in variability of grade within the quartz veins. This can result in high variability in the assay values for a sample. The 41 rock samples from the sampling programme were initially assayed using methods with 10-25g charges (Fire Assay and ICP-MS) that may not fully represent the gold grade of the material sampled.
To overcome this, all of the rock samples were resubmitted to the laboratory for gold analysis using the Intertek Laboratory LeachWell technique.
Intertek describes the LeachWell technique as a cyanide leach that utilises an accelerant to determine the cyanide extractable gold and provide a good indication of potential recoveries in metallurgical processes and circuits. The method can be conducted on samples of 200g up to 1,000g with a detection limit of 0.01g/t Au.
Golden Deeps is planning to undertake a diamond drilling program at Tuckers Hill once all drilling approvals are obtained. Provisional drill sites have been selected on the crest and eastern side of the hill where there is good access. Drill holes on the eastern side of the hill will test gold mineralised veins in the east limb of the Tuckers Hill anticline below previous underground mining. The holes from the crest of the hill will target saddle reefs in the apex of the anticline.
The drill sites are located on Crown Land Lots that have varying status that require land access agreements and heritage agreements with the Native Title claimants. Golden Deeps continues its engagement with the various stakeholders and the Native Title holders to gain access approvals for drilling. Rangott Exploration based in Orange, NSW is assisting with land access approvals.
EL9014 (Tuckers Hill) is an Exploration Licence that surrounds the historic Hargraves Goldfield near Mudgee in NSW. The Tuckers Hill project is at the northern end of Peak Minerals Pty Ltd’s Hill End Gold Project that has a Mineral Resource of 4.68Mt at 3.3g/t Au (501,552oz contained gold). There is little documentation of mining at Tuckers Hill prior to 1875, however, production figures from 1896 to 1908 and 1916 to 1939 indicate production of 1900 tonnes of ore with an average grade of 38.0g/t Au.
A compilation of previous exploration data and re-imaging of the aeromagnetic data has revealed five gold mineralised trends that are aligned in a north-northeast orientation, some of which are extensions of mined reef at Hargraves.
The priority targets are the Tuckers Hill and Maitland trends where sampling of historic workings and quartz veins returned high-grade gold values. Rock chip sampling of quartz veins and dumps at Tuckers Hill in 1981 returned multiple assay results over 1g/t Au with a peak value of 28g/t Au. The style of mineralisation is similar to Fosterville in Victoria where gold is contained in quartz reefs in the apex of tight anticlinal folds.