ASX-listed precious and base metals explorer, Godolphin Resources has jumped out of the gates in 2021 having simultaneously unveiled a revised mineral resource estimate for its historic Lewis Ponds polymetallic project in NSW’s coveted Lachlan Fold Belt region and kicked off a major drilling campaign in and around the resource area.
Following an exhaustive reassessment of historical drilling undertaken at Lewis Ponds across various periods over the past half a century, Orange-based Godolphin calculated a new mineral resource that, significantly, incorporates higher-grade precious and base metals mineralised zones.
The Lewis Ponds inferred resource now stands at 5.8 million tonnes of ore at an average grade of 2.1 grams per tonne gold, 83 g/t silver, 2.7 per cent zinc and 1.6 per cent lead for a contained metal content of 384,000 ounces of gold, 15.3 million ounces of silver, 158,000 tonnes of zinc and 93,000 tonnes of lead.
Prior to Godolphin’s revised resource numbers, there was an old inferred and indicated resource estimate ascribed to Lewis Ponds, 15 kilometres east of Orange, of 20.24 million tonnes of ore going 0.5 g/t gold, 33.3 g/t silver, 1.5 per cent zinc and 0.7 per cent lead.
Lewis Ponds was previously modelled largely as a base metals proposition. However, according to the company, its extensive review of historical drilling data last year highlighted the gold and silver potential of the project.
Godolphin pored over drilling data generated by previous owners that comprised more than 210 drill holes totalling 63,300 metres, with 58,425m of diamond drilling and 4,909m of RC.
As a result, it recently remodelled the Spicers Lode or Main Zone and Tom’s Lode, and geology at Lewis Ponds zeroing in on the higher-grade sulphide lenses identified by surface mapping and underground drill data. These encompass the higher-grade gold and silver mineralised portions with accompanying high zinc and lead values.
The company points out that historical drilling at Lewis Ponds included several high-grade gold and silver hits such as the impressive wide intersection of 91 metres grading 2.3 g/t gold, 79 g/t silver, 3.3 per cent zinc and 2.2 per cent lead.
The 148 square-kilometre project area is interpreted to be a splay of the Godolphin Fault, which is the same geological structure that hosts Regis Resources’ 2-million-ounce McPhillamys gold project, approximately 20km to the south-east.
Godolphin has decided to step on the gas and crank up its drilling intensity at Lewis Ponds courtesy of concurrent diamond and RC drill programs for total aggregates of 3,300 metres and 1,000m, respectively.
The three objectives of the drilling drive are resource definition drilling in and around the updated mineral resource area, drilling targets outside the newly estimated mineral resource for possible resource additions or extensions and gathering mineralisation composites with high precious metals content for bench-scale metallurgical test work.
Test work done a couple of years ago indicated a relatively simple flotation process producing two concentrates, a zinc concentrate and a lead-copper concentrate containing most of the precious metals.
A net smelter return, or “NSR” cut-off value of $140 per tonne was applied to estimate Godolphin’s revised Lewis Ponds mineral resource. The NSR, commonly used to assign a dollar value to polymetallic mineralisation, represents a predicted net recoverable value per tonne taking into account various key inputs.
They include combinations of gold, silver, zinc, lead and copper grades, recoveries associated with each of the processing streams, metal prices, payabilities, exchange rates and off-mine costs including freight, treatment charges and royalties.
Forecast metal recoveries from the concentrates based on the previous test work, which were also used in Godolphin’s independent resource consultants arriving at the average NSR value of $242 per tonne, were 60 per cent gold, 79 per cent silver, 92 per cent zinc, 75 per cent lead and 69 per cent copper.
Should commodity prices remain buoyant, and with historical mining and exploration at Lewis Ponds focused mainly on base metals with associated gold and silver as by-products, Godolphin may yet unlock the potential precious metals-bearing riches that previous owners left in the ground.
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