· Assays from four additional holes
· High grade gold intersections - 21.6m @ 6.02g/t Au, 12.25m @ 5.39g/t Au and 4.35m @ 2.53g/t Au.
· Polymetallic nature confirmed with high grade Zinc intersection of 19.85m @ 6.46% Zn and 21.60m @ 3.23%Zn, with minor Copper up to 0.8%.
· 4th rig to mobilise
London, February 22nd, 2021. Orosur Mining Inc. ("Orosur" or the "Company") (TSX/AIM:OMI), is pleased to announce an update on the progress of Minera Anzá's drilling campaign currently underway at the Company's Anzá project in Colombia.
To view the full PDF version of the announcement with Figures 1-3 included, please refer to this link: http://www.rns-pdf.londonstockexchange.com/rns/8115P_1-2021-2-21.pdf
Results of further four holes.
Diamond drill holes MAP-073, 074, 075 and 076 were completed during December 2020 and January 2021, with the holes positioned largely to address geological questions that were left unanswered from older drilling campaigns by previous companies.
Over 18,000m was drilled by Waymar Resources prior to it becoming part of Orosur in late 2014. Subsequent work by Orosur determined that much of this older drilling was oriented down dip, and while these holes often returned superficially attractive assay results, they did not provide sufficiently reliable geological information to fully understand the nature of the mineralisation and to allow accurate targeting and efficient expansion drilling.
As a result, much of the Company's initial 2,300m drill program currently underway, was designed to answer several outstanding orientation and structural questions and to provide insight into the style of mineralisation, with a focus on the potential for a hybrid polymetallic VMS/Epithermal model.
These four holes were drilled on three sections, and returned attractive gold intersections, assisted in addressing key structural questions, and returned wide intersections of high-grade Zinc that added weight to the polymetallic VMS model. Key intersections include (full intercepts are detailed in table 1):
MAP-073 21.60m @ 6.02g/t Au, 6.02g/t Ag and 3.23 %Zn from 271.75m
MAP-074 5.20m @ 1.17g/t Au 4.97g/t Ag and 3.02% Zn from 195.40m
MAP-075 19.85m @ 0.90g/t Au 2.17 g/t Ag and 6.46% Zn from 226.15m
MAP-076 12.25m @ 5.39g/t Au, 1.65 g/t Ag and 0.18 % Zn from 228.65m
Table 1. Drill Intercepts*.
(* Intersections are reported as down-hole widths, not true widths. The Company does not yet have sufficient drilling information to accurately calculate true widths of drill hole intersections)
MAP-073 and MAP-076
MAP-073 and MAP-076 were drilled on the same section (Fig 1)
Fig1. Section, Holes MAP-073, 076
Both holes were drilled to assist in resolving a geological interpretation issue in the south of the APTA zone, that had resulted from earlier holes having been drilled toward the east or having stopped short of the mineralised zones.
Both holes were successful in resolving the questions posed, and both returned substantial intersections of high-grade gold and moderate zinc as reported.
MAP-074 was drilled up dip of a group of previous holes that had defined a complex zone of gold mineralisation (Fig 2).
Mineralisation in MAP-074 was thinner than expected, and lower gold grade, but like hole MAP-075 showed enhanced zinc grades.
Further work will be done, however drilling further up dip with hole MAP-078 visually shows a thinner breccia package and might suggest the breccia zone is pinching out in this direction. This information is important for gaining a greater understanding the orientation and zonation of the orebody and is essential for targeting.
To this end, hole MAP-080 has just been commenced down-dip.
Fig 2. Section, Hole MAP-074
Hole MAP-075, High Grade Zinc
Hole MAP-075 was drilled some 90m down dip of the previously announced MAP-072.
Fig 3. Section, hole MAP-075
Visually, the mineralisation within the breccia zone intersected in MAP-075 was similar to that intersected in MAP-072, however assay results would suggest MAP-075 has intersected a different mineralogical domain, transitioning from a domain that was gold dominant with secondary zinc, to one that is zinc dominant with secondary gold.
Zinc mineralisation in hole MAP-075 is at times massive, with grades in excess of 30% over small intervals. Both MAP-072 and MAP-075 also contain minor copper, roughly correlated with zinc, with grades at times as high as 0.8% Cu.
Such zonation is expected and is an integral characteristic of Volcanogenic Massive Sulphide (VMS) deposits. However, given the orientation problems of previous drilling, this was the first hole to show this zonation so unequivocally and so provide tangible guidance for further targeting.
Hole MAP-077 has been completed and was located an additional 90m down dip of MAP-075 and has visually demonstrated similar intersections of massive sulphide and pervasive silicification. All samples from MAP-077 have been submitted for assay and once returned, will provide additional guidance that should assist in further developing an understanding of the zonation within the VMS system.
Mobilisation of 4th rig
The preliminary 2,300m drill program has now been largely completed and as planned, has addressed a number of outstanding geological questions. This has provided valuable guidance as to the nature and distribution of the mineralisation at APTA that will allow future drilling to be more efficiently targeted.
A decision has now been taken to move into the next phase of drilling with a 7,000m program and to that end, a 4th diamond drill is to be mobilised to site in coming days.
Orosur CEO Brad George commented:
"After much excellent work and several phases of drilling, it is pleasing to be at the point where we are now developing a greater understanding of APTA, its nature and genetic controls. It is also testament to the benefits of being in a JV with major companies that gives us access to a depth and breadth of experience and technical expertise that Orosur alone does not possess.
The emerging picture of APTA as a polymetallic, gold rich, VMS deposit is both an opportunity and a challenge - a challenge in having to now understand the zonation that is inherent in VMS deposits, but an opportunity in that the polymetallic nature (especially at high grades) is invariably a positive for project economics"