Orea Mining Corp. has reported on the 2020 drilling programme at the Maripa gold project located in French Guiana.
- 8 diamond drill holes were completed to date on the Maripa exploration permit.
- 6 of the 8 drill holes served to test the depth and lateral extent of 3 gold mineralised shear-hosted vein systems traced at surface.
- 4 drill holes intersected wide shear zones marked by quartz veining, strong hydrothermal alteration, and sulfide mineralisation over 18 – 27 m.
- Re-sampling of historical core of drill hole MAR-06-008 confirmed original results with new results averaging 4.07 g/t gold over 36 m.
- Initial results from the current drill programme have confirmed gold mineralisation in the shear zones.
- The structural model for follow-up drilling is being re-assessed in light of the initial drilling results to establish the controls on higher-grade gold mineralisation as obtained in surface samples and historical drill holes.
The 2020 diamond drilling operations were carried out from 15 October – 25 November with one drill rig. A total of 8 diamond drill holes were completed for a total 1168 m. The drill holes tested 4 separate targets on the Maripa exploration permit, one of five exploration permits making up the Maripa gold project:
- Drill holes MAR-20-013, -015 and -016 (3) further investigated the Filon Dron shear-vein system discovered in 2006 with best drill hole intersections of 2.45 g/t Au over 25.5 m and 4.18 g/t Au over 36 m.
- Drill holes MAR-20-012 and -014 (2) provided an initial test of artisanal mining Site #1 shear-vein system discovered during the 2019 prospecting programme with best surface sampling results of 5.84, 11.45 and 86.8 g/t Au.
- Drill hole MAR-20-011 (1) provided an initial test of artisanal mining Site #4 shear-vein system also discovered during the 2019 prospecting programme with best surface sampling results of 6.36, 6.6, 9.7, 11.08, 13.07 and 15.22 g/t Au.
- Drill holes MAR-20-017 and -018 (2) investigated untested gold-in-soil anomalies along the faulted contact between Paramaca Formation volcanic rocks and upper detrital unit (UDU) sediments.
The promising Filon Dron prospect located in the central part of Maripa, is one of the five partially drill-defined gold zones at Maripa. The initial discovery drill program at Filon Dron, consisting of seven shallow core holes carried-out by IAMGOLD Corp. in 2006, was limited to a 400 m by 200 m area of an extensive gold-in-soil anomaly. Two of the 7 cored holes returned important gold mineralised intersections within the surface weathered saprolite layer of 2.45 g/t Au over 25.5 m, including 3.17 g/t Au over 13.5 m, obtained in drill hole MAR-06-007, and 4.18 g/t Au over 36 m, including 7.17 g/t Au over 18 m, obtained in drill hole MAR-06-008, defining a wide gold mineralised zone striking north-northwest, parallel to the local stratigraphic and structural trends.
Prospecting by Orea in 2019 and 2020 led to the discovery of 3 additional shear-hosted vein systems exposed by artisanal mine workings (Sites #1, #4 and #5) in proximity to Filon Dron. Select samples of quartz veins and wallrock collected from the artisanal mine workings and ore stockpiles returned high-grade gold values at all 3 prospects, including:
- 5.84, 11.45 and 86.8 g/t Au at Site #1.
- 6.36, 6.6, 9.7, 11.08, 13.07 and 15.22 g/t Au at Site #4.
- 38.87 g/t Au at Site #5 (see Orea’s news release dated 26 September 2019, 26 November 2019 and 12 May 2020).
Drill core from the current drill programme obtained in fresh rock, below the surface weathered saprolite zone, indicated that the Filon Dron, Site #1 and Site #4 structures are typical of shear-hosted mesothermal gold mineralisation characterised by a penetrative structural fabric, strong sericite-carbonate alteration and injected with a network of shear and tension veins composed of an assemblage of quartz, carbonate and lesser tourmaline. The veins and wallrock are mineralised with up to 2% to 7% sulfides as pyrite and lesser chalcopyrite. Specks of visible gold were observed in drill holes MAR-20-012 and -013. The shear zones cut intermediate and mafic volcanic rocks of the Paramaca Formation.
2020 Drilling programme results
True widths are estimated at 80% of core length based on core angles with the dominant structural fabric.
Drill holes MAR-20-013, -015 and -016 investigated the Filon Dron structure over a NW-SE strike extent of 400 m.
- MAR-20-013 provided a 100 m step out from the intersection of 4.18 g/t Au over 36 m obtained in historical drill hole MAR-06-008. The drill hole cut a 24 m sheared, veined, altered and sulfide mineralised section that returned assays averaging 1.61 g/t Au over 6.6 m.
- quarter core splits of historical hole MAR-06-008 confirmed the original results with new results averaging 4.07 g/t Au over 36 m.
- MAR-20-015 tested 50 m downdip from the intersection obtained in historical hole MAR-06-008. A best assay of 3.32 g/t Au over 1 m was returned.
- MAR-20-016 provided a 125 m step out to the north from the intersection of 2.45 g/t Au over 25.5 m obtained in historical hole MAR-06-007. The hole was drilled within the surface weathered saprolite zone. A best assay of 3.25 g/t Au over 1 m was returned.
Drill holes MAR-20-012 and -014 were spaced 300 m apart along the NW-SE strike extent of the structure traced at surface:
- MAR-20-012 cut a 27 m sheared, veined, altered and sulfide mineralised section that returned assays averaging 2.55 g/t Au over 6.1 m, including 3.54 g/t Au over 4.3 m.
- MAR-20-014 cut an 18 m section of quartz veining within saprolite that returned assays averaging 0.5 g/t Au over 1.9 m.
Hole MAR-20-011 investigated Site #4 structure traced at surface. The drill hole was positioned to test the depth extent of a 3 m wide quartz vein exposed at surface in artisanal mine workings. Sampling of the vein at surface had returned a best assay of 15.22 g/t Au. MAR-20-011 cut a 20 m sheared, veined, altered and sulfide mineralised section with veins up to 40 cm wide. Best gold mineralised sections obtained include 0.78 g/t Au over 4.95 m, 1.77 g/t Au over 1.15 m, 1.01 g/t Au over 3.6 m and 0.74 g/t Au over 1.8 m.
Paramaca / UDU contact zone
Drill holes MAR-20-017 and -018 served to investigate gold-in-soil anomalies along the faulted contact between volcanic assemblages of the Paramaca Formation and younger pull-apart basin sediments of the UDU. The contact is recognised to be favourable loci for gold mineralisation. The drill holes principally traversed arenitic sandstones cut by sparse quartz veins. No gold significant gold values were obtained.
Interpretation and follow-up
Structural controls and orientations of high-grade gold mineralised vein sets and vein stockworks within the targeted shear zones are being re-assessed in light of the initial drilling results. The 2020 drill holes were preferentially oriented to cut at high-angle the subvertical shear vein sets developed parallel to the dominant structural fabric. High gold content is potentially associated with vertically staked high density tension vein stockworks developed within the subvertical shear envelops. Follow up drill holes are being designed with alternated hole orientations to test for staked high density vein stockworks.
Read the article online at: https://www.globalminingreview.com/exploration-development/28012021/orea-reports-on-maripa-gold-project-drilling-programme/