Archer Materials Ltd (ASX:AXE) has received positive drill results from its 100%-owned Eyre Peninsula Halloysite-Kaolin Project (EP) in South Australia with high-grade, near-surface kaolin intersected.
A 21-hole aircore drill program at the EP Project comprised seven holes drilled at Kelly Tank prospect, 11 holes at Bunora prospect and three holes at Bunora East prospect.
The drilling was successful in recovering kaolin which in some instances has reported grades of up to 36.8% aluminium oxide over downhole lengths of 18 metres.
Archer executive chairman Greg English said: “We are pleased with the results from the latest drilling at the EP Project with high-grade kaolin intercepted from the surface.
“To intercept high grade kaolin near the surface is a great result.
“The drill results from the EP Project complement the recent drill and metallurgical test results from the Franklyn Halloysite-Kaolin Project.
“As a company, we are fortunate to have two substantial discrete halloysite-kaolin projects at Franklyn and the Eyre Peninsula”.
The Franklyn Halloysite-Kaolin Project is 220 kilometres east of the EP Project.
Location of holes drilled by Archer (red) this year and holes drilled by a previous explorer in 2014 (yellow)
Kelly Tank kaolin
The latest drill results were purposely designed to confirm historical drill results.
In the 1970s, Pechiney drilled more than 30 holes in the area of Kelly Tank in the search for kaolin to be used in the paper filling and coating industry.
However, the poor rheological properties (the inability of the kaolin to make a fluid slurry comprising 70% clay) was the main reason the kaolin material was subsequently deemed by Pechiney to be unsuitable.
Archer believes that the presence of halloysite in the kaolin may be the reason for the poor performance of the kaolin as halloysite has such a high surface area that it requires more dispersant to be able to obtain a 70% solids slurry.
High-grade recoveries
From the seven holes drilled, a total of 21 composite samples were selected and submitted for screening and assay, and the composite intervals range from 2 metres to 5 metres in length.
All -45 micrometre size fractions reported grades above 30% aluminium oxide, with various intervals reporting above 35%.
The most significant interval of kaolin was from the surface to a depth of 19 metres and the smallest interval was from 1-metre to 5 metres.
Archer has achieved recoveries up to 59% with grades of 34.8% aluminium oxide.
Holes drilled by Archer at Bunora (red) this year and holes drilled by Pechiney in 1970s (blue)
Bunora prospect
In the 1970’s Pechiney drilled around 30 holes in the Bunora area.
Archer’s 11 holes ntersected numerous intervals of white kaolin from 4 metres of the surface to greater than 20 metres below the surface.
Screened samples showed recoveries of up to 71% achieved with grades of 36% aluminium oxide.
Bunora East prospect
Pechiney drilled eight holes at Bunora East in the 1970’s which Archer followed up with three more.
The company also recovered drill material from three (angle dip) holes drilled in 2014 and these samples were submitted for analysis.
All the new drill holes report kaolin from within 1-metre of the surface, with one drill hole reporting more than 30% aluminium oxide to a depth of 26 metres, the other two holes report intervals down to depths of 7 to 8 metres.
Recoveries of more than 90% have been achieved with many intervals reporting a screened grade above 35% aluminium oxide.
Holes drilled by Archer (red) this year; holes drilled by a previous explorer in 2014 (yellow) and holes drilled by Pechiney in the 1970s (blue)
Next steps
Drilling showed that the geology appears slightly different at each of the prospects, which may offer opportunities to develop products with different halloysite and kaolin specifications.
White kaolin was recovered from each prospect with the fine screened fraction reporting the favourable result of low iron impurity levels.
Results from the latest drilling and test work will allow the company to accurately target and focus future exploration efforts - and de-risk the development of the EP Project.
As the Franklyn project is more advanced in development, Archer intends to review the results of the Franklyn beneficiation before undertaking further test work at EP Project.