Lefroy Exploration Limited (ASX: LEX) has commenced major reverse circulation (RC) drill programme at the Burns Au-Cu intrusion-related mineral system, located in the company’s wholly owned Eastern Lefroy Gold Project, 70km southeast of Kalgoorlie.
Burns is a new and unique style of intrusion-related, gold (Au)-copper (Cu)-molybdenum (Mo)-silver (Ag) mineral system, hosted by Archean age diorite-porphyry intrusives and high-magnesium basalt in the Eastern Goldfields Province (EGP) of Western Australia.
This is another exciting period of exploration at Burns and immediately following on from the completion of the four diamond drill holes both at Burns and Lovejoy,” Managing Director, Wade Johnson, said.
“The RC drilling is focussed on the shallow portion of the larger Burns system and designed to deliver a maiden gold copper resource. This close spaced drill data will also provide detailed geological information to guide further deeper exploration at Burns and also at multiple targets along the Burns corridor”
A maiden 22-hole RC drill programme completed in Jan-Feb 2021 intersected a spectacular gold and copper interval in hole LEFR260 containing 38m @ 7.63g/t Au & 0.56% Cu from 134m. The results from that RC programme provided the geological and geochemical data that highlighted the unique geological characteristics of Burns and was a key parameter to subsequent and ongoing exploration activity.
Targeted aircore, RC and diamond drilling at Burns since January 2021 has established the broad footprint of the system but with the limit of mineralisation yet to be fully defined.
Interrogation of 3D metal models including gold (Au), copper (Cu) and molybdenum (Mo) sourced from an extensive multi-element drill database collected over the Burns project since January 2021, has provided an enhanced interpretation of the geometry of the Burns mineral system.
That work highlighted a large, northwest trending, southerly plunging mineralised (Au, Cu, Ag, ± Mo) shell. Included within this shell is a higher-grade, northerly trending Au-Cu component which was recently tested with diamond holes (LEFD006 and 007a).
This northerly trending, high-grade zone is further supported by the recent multiple aircore (AC) gold intersections in Lake Randall, 240m north of discovery hole LEFR260. This included an intersection of 24m at 2.86g/t Au from 16m in LEFA1089, hosted within diorite porphyry and obscured by transported overburden.
Reverse Circulation (RC) Resource Drill Programme
Following on from the recent diamond drilling, which focussed on the deep vertical extent of the system, an RC drill program to evaluate the economics of the system to 200m from surface and over a 700m strike length has commenced and underway.
The planned resource drilling will be both land-based (onshore) and on Lake Randall (offshore). The drilling will be on a 40m by 40m spaced grid pattern with angled holes planned at nominal 250m final depth. The new drill data when combined with existing drill data, will form the basis for a maiden gold-copper resource estimate.
A specialised lake RC drill rig has been secured and scheduled to commence in late October 2022.
Subject to assay result turnaround, the company aims to deliver a maiden resource estimate for the shallow part of the Burns system in the March 2023 Quarter.