Great Northern Minerals Limited (ASX: GNM) has announced high-grade intersections including up to 81.68g/t gold from the RC drilling programme at its Big Rush Gold Project in Northern Queensland.
The company said that all one metre individual resplits returned from Big Rush confirmed high grades and significant widths over 900 metres of strike length. GNM said that a deeper diamond drilling program to further test these zones at depth would commence in the second week of October.
Important high-grade results include 19m @ 5.11 g/t Au (BRRC1014) including 3m @ 21.73 g/t Au from 77 metres; 32m @ 1.32 g/t Au (BRRC1015) from 132 metres; 28m @ 1.27 g/t Au (BRRC1018) from 91 metres; and 8m @ 4.40 g/t Au (BRRC1030) from 155 metres
The company said that the drill program unlocks potential for a large gold resource at Big Rush with gold mineralisation confirmed and extended by this program.
GNM said that diamond program is due to commence shortly to evaluate and follow up at depth some of the more significant intersections.
Big Rush gold mine
The Big Rush Gold Mine in Northern Queensland consists of four previously mined open pits which produced 950,000 tonnes @ 1.90 g/t Au for 58,039 ounces via heap leaching and produced 33,000 tonnes of sulphide ore @ 11 g/t Au for 10,000 ounces by trial CIL Processing.
Big Rush project is part of the Golden Ant group of projects that GNM had acquired in August 2019. Other projects include the former Camel Creek and Golden Cup gold mines.
Big Rush is located on 3 granted Mining Leases MLs 10168, 10175, and 10192 which are held by Alphadale Pty Ltd. There were 4 pits mined over 1.7 km of strike length with the depth of mineralisation again being limited to the oxide zone.
RC drilling at Big Rush
GNM had recently commenced a Reverse Circulation (RC) drilling programme at the Company’s Big Rush Gold Project in Northern Queensland.
The total recent drilling at Big Rush comprised 22 RC holes (BRRC1012 to BRRC1033) for 3,634 metres spread over approximately 900 metres of strike underneath the southern, central, and northern previously mined shallow open pits. The drill hole depths ranged from 110 to 250 metres depth and averaged 165 metres.
Great Northern said that it has now completed phase one of the drilling program at Big Rush. The company has now reported the results of all of the one metre resplit samples from RC holes BRRC1012 to BRRC1033.
High-grades and significant widths
GNM reported that the phase one of the drilling program at Big Rush has returned a number of high-grade gold results.
The company has now reported results from all of the one metre resplit samples from RC holes BRRC1012 to BRRC1033 as well as the previous 4 metre composite results previously released to the ASX on the 16 and 17 September 2020.
High grade intersections include 19m @ 5.11 g/t Au (BRRC1014) including 3m @ 21.73 g/t Au from 77 metres; 32m @ 1.32 g/t Au (BRRC1015) from 132 metres; 28m @ 1.27 g/t Au (BRRC1018) from 91 metres; 26m @ 1.99 g/t Au (BRRC1019) including 2m @ 17.56 g/t Au from 119 metres; 20m @ 1.28 g/t Au (BRRC1024) from 106 metres; 11m @ 3.27 g/t Au (BRRC1025) from 144 metres; 37m @ 2.28 g/t Au (BRRC1026) from 148 metres; and 8m @ 4.40 g/t Au (BRRC1030) from 155 metres.
Great Northern said that the one metre results have highlighted the higher-grade gold zones lying within a number of the larger lower grade mineralised zones and provides a clear focus for targeted deeper diamond drilling designed to test at depth these higher-grade intersections.
Mineralisation extended
The company said that these results have significantly extended the known mineralisation to greater than 150 metres vertical depth with the strike extent under the northern pit now confirmed in excess over 250 metres.
GNM said that the total strike length of the mineralisation at Big Rush based on the previously mined open pits and plus 1.0 g/t Au assays extends over 2.3 kilometres of known strike. The company noted that this current program has tested approximately one kilometre of strike with continuity and high-grade zones outlined and confirmed.
Deeper diamond program planned
GNM said that planning for a deeper diamond program is well underway and due to commence in the second week of October. This more detailed drilling is expected to allow the company to focus in on a possible late stage higher grade mineralisation event and associated vectors.
The company said that initially four diamond holes (and precollars) to an approximate depth of 260 metres are planned underneath the central pit and one diamond hole to a similar depth is planned underneath the northern pit. This will allow detailed interpretation of the diamond core, provide representative samples for metallurgical testwork and allow for greater knowledge leading to an updated JORC 2012 estimate for the Big Rush gold deposit early in 2021.
Next steps
GNM reported that further work will include drill testing for extensions to the known mineralization, mostly down dip; additional metallurgical test work to determine the most appropriate process route for gold recovery; and completion of an initial Scoping Study on the economics of developing a gold producing operation at Big Rush.
Management comments
GNM Managing Director Cameron Mclean said: “The one metre results have confirmed the potential for very high grades to extend to significant vertical depth, particulary underneath the Central Pit.
Results from underneath the Northern Pit are pointing to excellent further potential in this area and the planned deeper diamond drilling program which is about to commence is designed to test for extensions of the higher-grade gold results.
Anomalous gold mineralisation at Big Rush is now documented to occur over at least one kilometre of strike, with additional strike extensions apparent.”