Australian explorer Thomson Resources (ASX: TMZ) has commenced a high-resolution airborne magnetic survey west of its Chillagoe gold project in far north Queensland to help define intrusion related mineralisation targets.
The 3,000 line kilometre program will be partially funded by a $100,000 grant from the Queensland Government under its collaborative exploration initiative.
The survey area will cover several prospects which have returned strong surface geochemical results from previous exploration but are yet to be drill tested.
These include Laverock, where a rock chip assayed 16 grams per tonne gold, 64g/t silver, 20% copper and 0.4% tungsten; Borderline, where a continuous 1.5m channel sample returned 28.6g/t gold and 713g/t silver; and Salt Creek where rock chips ranged up to 5.7g/t gold.
In 2020, Thomson tested a number of existing magnetic targets with soil and rock chip sampling, producing strong gold results and identifying two parallel 700m-long anomalies at Borderline.
Intrusion related gold
The Chillagoe project covers an area of 594 square kilometres and comprises seven mineral exploration permits in which Thomson holds a 90% interest with the remaining held by major shareholder Bacchus Resources.
The principal target type in the area is intrusion related gold (IRG) which is typically associated with felsic carboniferous breccia pipe and intrusive complexes.
In this area several such bodies are known and display features typical of the nearby Mungana and Red Dome IRG deposits, where late carboniferous intrusions and breccias are hosted by predominantly limestone host rocks.
Within Chillagoe, late carboniferous intrusions are hosted by older basement rocks such as palaeozoic and proterozoic age intrusives, schists and gneisses.
To the project’s south, the Kidston and Mt Leyshon IRG deposits are also associated with permo-carboniferous igneous intrusions into older rocks.
These deposits have “great vertical extent”, with Red Dome having a proven depth continuity greater than 1,000m.
Thomson said the exploration implication is that most undiscovered deposits of this type will come close to surface, only hidden by weathering and recent alluvial or transported sediments.