Sunstone Metals Limited (ASX: STM) has announced extensive intersections of mineralisation at the Limon prospect within the Bramaderos project in southern Ecuador.
STM reported that the hole LMDD002 intersected more than 200m of visible and persistent disseminated chalcopyrite and molybdenite with some bornite in a strongly altered porphyry system.
LMDD002 was terminated at 893.58m, with assay results expected before the end of June.
It may be noted that STM’s first hole at Limon, LMDD001, was drilled below an interpreted plunging mineralised porphyry intrusion.
STM said that the next drill hole will be undertaken at the Bramaderos Main target to follow-up on historical hole CURI-03. The drilling is anticipated to return to Limon once all assays for hole LMDD002 are received.
Sunstone Managing Director Malcolm Norris said it was an extremely promising result. “This is an outstanding start and we expect the next few holes at Limon to deliver some very good results.”
The Bramaderos gold – copper project
The Bramaderos gold-copper project is located in Loja province, southern Ecuador, and is considered to be highly prospective for the discovery of large gold-copper systems.
Historical results from drilling at Bramaderos, together with the distribution of alteration, and large coincident gold-copper-molybdenum surface anomalies indicate multiple fertile mineralised systems with significant discovery potential.
Sunstone had signed an earn-in agreement with Cornerstone Capital Resources for the Bramaderos gold-copper project.
First drill hole LMDD001
STM’s first drill hole, Hole LMDD001 was completed on April 25 at a depth of 490.6m (vertical depth of 340m).
LMDD001 had intersected a narrow interval of weakly mineralised porphyry 90m below the surface mineralised trench. Assay results from LMDD001 included 18.6m at 0.24g/t gold, 0.1% copper, and 70.8ppm molybdenum from 90.4m downhole.
Interpretation of the results suggested that the drill hole has cut underneath a plunging finger of mineralised porphyry that extends from the surface trench which delivered 97.6m at 0.71g/t gold and 0.23% copper.
Extensive intersections at drill hole LMDD002
LMDD002 is STM’s second hole drilled at Limon prospect within the Bramaderos project in Ecuador.
The company said that LMDD002 has intersected a very encouraging interval of porphyry-related mineralisation with visible and persistent chalcopyrite and molybdenite, minor bornite, anhydrite veining, and widespread pyrite in quartz stockwork B-veining in the lower parts of the drill hole.
This indicates that the intersection was likely drilled adjacent to the core of the system where enhanced accumulations of copper and gold are probable.
STM said that the Hole LMDD002 was drilled from outside the interpreted porphyry system towards the interpreted centre and has exhibited very strong zoning supporting that interpretation.
LMDD002 was terminated at 893.58m. Although the originally planned end-of-hole was 600m, the very encouraging visual results made STM push the hole deeper. Drilling averaged approximately 35m per day.
STM said that a potential higher-grade portion is currently interpreted to lie northeast to east of hole LMDD002, where it may extend to shallower levels if LMDD002 drilled down through the southwest fringe of the main system.
It may be noted that Gold mineralisation in the drill core cannot be detected by visual inspection and will only be revealed by the assay. Assay results for hole LMDD002 are expected before the end of June.
The company said that the understanding of the geometry of the Limon porphyry system is evolving.
STM said that following the completion of LMDD002, the company awaits full assays at Limon and is planning for follow-up drilling. Currently, the drill rig is being moved to the Bramaderos Main target (2.5km south-west of Limon).
The company said that the first hole at the Bramaderos Main porphyry target will drill below the historical intersection of 248m at 0.56g/t gold and 0.14% copper in hole CURI 3, and below recent surface trenching that had delivered 615m at 0.52g/t gold and 0.11% copper.
The company’s overall Phase 1 drilling program across the three targets of Limon, Bramaderos Main and West Zone is anticipated to be approximately 5,000m. Drilling at the West Zone target is expected to follow later in the program, where surface trenching had delivered 15.6m at 6.1g/t gold.
Sunstone Managing Director Malcolm Norris said: “We are very encouraged by these early results at Limon. We have drilled two diamond holes into parts of a new mineralised porphyry system and its associated large-scale alteration zone but are yet to test the core of the system, which is our primary target. The drill core clearly show good development of ‘B veins’ containing some chalcopyrite and molybdenite and local minor bornite. Results from drilling and from surface datasets confirm we are in a porphyry system.