Caspin Resources Limited (ASX: CPN) has received significant rare earth element results from the Duchess Prospect at the 100% owned Mount Squires Project in Western Australia.
These are the first results from the 4,500m RC program conducted during June, with results still pending from a majority of the drilling. Drilling was completed to test several REE, gold, nickel and copper targets across the project.
This is a great start to our Mount Squires drill program which tested several targets and commodities across the Project. Results returned from only a small number of holes have demonstrated that there is growing potential for a large deposit of rare earth mineralisation at Mount Squires, a region that has never had systematic rare earth exploration. The mineralisation remains open in multiple directions with no previous drilling of the controlling structures,” CEO Greg Myles said.
“Importantly, this mineralisation contains an exceptionally high proportion of heavy rare earths, which are many times more valuable than the light rare earths which dominate the profiles of many Australian rare earth projects. This offers Caspin a unique position amongst its peers. It is also encouraging to recognise rare earth mineralisation associated with monazite, a common rare earth ore mineral with a well understood processing route.
“We look forward to the return of the remaining rare earth assays, as well as gold, nickel and copper results from the remainder of our programme.”
The primary goal of the drill programme at the Duchess Prospect was to step out and extend REE mineralisation from the initial discovery in drillhole MSAC0141 (46m @ 0.71% TREO including 22m @ 1.25% TREO). The company has drilled a pattern of nine holes on approximately 100m centres stepping out from MSAC0141, particularly focussing on apparent geological contacts and faults that may control mineralisation. An additional three holes (MSRC0008-MSRC0010) have been drilled to the southeast at Duchess East which has coincident base metal and REE mineralisation. Assays from the first 7 holes have now been returned.
The programme has successfully identified broad extensions of mineralisation such as 27m @ 0.70% TREO including a higher-grade zone of 12m @ 1.15% TREO comprising 1,662ppm neodymium (Nd), 404ppm praseodymium (Pr), 325ppm dysprosium (Dy) and 54ppm terbium (Tb) in MSRC0003 and 12m @ 0.81% TREO including a higher-grade zone of 6m @ 1.15% TREO comprising 1,946ppm Nd, 455ppm Pr, 296ppm Dy and 51ppm Tb in MSRC0006. Deleterious elements such as uranium and thorium are low, averaging less than 20ppm and 10ppm respectively.
Mineralisation appears to be controlled by a northwest-southeast striking fault at the contact between volcaniclastic and rhyolitic host rocks. The prospect is also cross-cut by a late-stage dolerite dyke, possibly exploiting a northeast-southwest striking fault that offsets (by ~200m) the volcaniclastic-rhyolite contact. These faults have provided pathways for hydrothermal fluids to mobilise REEs which have then been deposited at points of rheological contrast such as the volcaniclastic-rhyolite contact. There is also an association of mineralisation on the dolerite contacts.
Many of the significant intercepts occur in weakly weathered rock or saprock, indicating potential further enrichment through weathering processes.
Mineralisation remains open along both the volcanoclastic-rhyolite and dolerite contacts over at least 1,000m which presents further opportunities for discovery. Some of the company’s earlier aircore drilling is now recognised as being an ineffective test of REE mineralisation, due to a lack of depth penetration.
The primary source of REE mineralisation is uncertain but is likely from the rhyolite itself.
The large proportion of heavy rare earth elements (HREE), such as Dy and Tb, is highly significant given the much greater value of these metals compared to light rare earth elements (LREE) such as Nd and Pr.
The company has observed that the proportion of HREE to LREE can vary significantly, ranging from 23% in MSRC0003 up to 73% in MSRC000. Note the higher grades of Dy and Tb in MSRC0001 are comparable to intersections in MSRC0003 and MSRC0006, despite the overall lower TREO values and are considered just as significant. MSRC0001 terminated in mineralisation >1,000ppm TREO and may need to be extended.