The Boulanger Project is located approximately 40 km south of Cayenne, the capital of French Guiana. Access to the project is by National Road No. 2 and a network of laterite roads (figure FG 1).
Mineral rights and option agreement
In July 2017, Reunion entered into an option agreement to acquire a 100% interest in the Boulanger, Central Brief, Devez North, and the Devez South mineral concessions along with the Carapa mining permit (previously known as Ste-Marie; figure B1). The four concessions, which cover an area of 78.2 km², were originally granted to Compagnie Minière de Boulanger (CMB) by the French government in late 1880 and early 1920s. Due to recent amendments to the French mining code, all concessions expired on December 31, 2018. CMB has filed applications to renew the concessions for a total area of 39 km², which will cover all the main exploration target areas.
The Saint-Michel prospect is located within a one square kilometer small scale mining permit (AEX) encircled by the Chawari exploration permit (PER) application and both were added in 2019 to the option agreement between Reunion Gold and CMB. The option can be exercised up to July 27, 2021. To exercise the option, Reunion has to pay 1,000,000 € to CMB upon exercise and 1,000,000 € upon receipt of all regulatory approvals.
Figure FG 1: Location of CMB properties
Figure B1: Schematic geological map of the Boulanger Project region showing mineral rights and gold prospects (yellow stars).
Geology and mineralization
The Boulanger Project is underlain by Armina and Paramaca volcanic and sedimentary rocks or Proterozoic age, intruded by granites and metamorphosed to greenschist facies (Figure B1). The Project area is cut by various shear zones characterized by intense deformation and recrystallization with evidence of hydrothermal fluids rich in sulphides and gold, associated with quartz veins, pyrite, and locally intense tourmaline alteration. Geological mapping and soil geochemistry done by Asarco indicate numerous anomalous zones that require follow-up exploration.
Mining and Exploration History
The Boulanger Project is in a historical gold producing area, both from placer and primary sources. CMB has been carrying out small-scale alluvial gold mining operations on the mining concessions. Asarco explored portions of the Project area in the 1990’s, followed by Cambior and Iamgold. These operators conducted extensive geological mapping, nearly 7,500 soil geochemical samples, trenching and over 12,000 m of diamond drilling in the nineties, but stopped short from publishing a mineral resource estimate for the several prospects in the area. This work outlined gold occurrences characterized by quartz/tourmaline veining in volcanic and intrusive rocks cut by strong shearing.
Following compilation of historical data and relogging available core, Reunion set out to systematically explore the known prospects, verify their relationships and attempt to define mineral resources. Key new exploration tools brought to the project included a heliborne magnetometry and radiometry survey over the entire area, and induced polarization geophysical surveys over specific targets (Doyle, Devez, STM 1-2-5, Crique Filon and St-Michel). These tools generated new targets and helped update geological, geochemical, and geophysical interpretation.
Crique Filon prospect
This prospect straddles the limit between the Doyle concession and the Carapa permit, located 500 m east of the Doyle prospect. In 2018, two Reunion drill holes (CB-18-08 and 09) tested the prospect and intersected significant gold mineralization (table B1), including visible gold in hole CB-18-08, interpreted to be shear-controlled and thus confirming the need to do follow-up drilling.
Table B1: Crique Filon prospect 2018 drilling results
During the second quarter of 2019, eight new IP gradient survey lines totaling eight kilometers were completed to cover fold closures of the 2018 survey at the Carapa exploration permit and Central Bief concession, along with four lines of pole-dipole to provide additional information on the suspected fold closures and better define drill targets. This was followed by an 1,100-meter core drilling program in six drill holes in June. Of interest are the holes drilled at Crique Filon, where the eastern extension of a shear was cut by two significant intersects in hole CA-19-05 (table B2 and figure B2).
Table B2: Crique Filon prospect 2019 drilling results
Figure B2: Map of the Crique Filon area, showing IP chargeability background, intersections from drill holes (black = historical, red = Reunion Gold) and interpreted shear zones.
On hole CA-19-05, a first high-grade section from 22.5 to 24.1 m consists of andesite saprolite with quartz tourmaline probably in tension veining and averages 6.68 g/t gold over 3.1 m. A second section at 9.73 g/t gold from 41.0 to 42.0 m is at the beginning of a three-meter-thick shear zone.
An additional 300-meter core drilling program in two diamond drill holes was done in September 2019 to follow-up on shear and tension vein mineralization identified in drill hole CA-19-05. Of interest are three significant intercepts:
Hole CA-19-06A: 6.02 g/t gold over 7.56 m. This high-grade section starting in saprolite from 11.94 m is a re-drill of the top section of hole CA-19-06 with insufficient core recovery.
4.66 g/t gold over 5.65 m, starting from 9.00 m in saprolite.
4.30 g/t Au over 4.0 m from 123.5 to 127.5 m.
It has become apparent that several shear zones occur in the Crique Filon area. The recent drilling cut tension veins and strongly foliated and sheared andesitic volcanics associated with the two shear zones intercepted in CA-19-05. This confirms the interest of targeting for future drilling both the shear veins and their associated tension veins. These shear zones can be traced over 300 m and 200 m, respectively and remain open on strike and at depth. Several other attractive shear zones are found in the same area, to be further tested by drilling.
This area was explored by Asarco in the 1990’s with over 4,000 m of drilling and by CMB, with 1,175 m of drilling in 2016. CMB also mined primary gold mineralization and alluvial placer in the Doyle area.
In 2018, Reunion completed an initial 1,025 m drilling program to confirm historical mineralization in the northeastern corner of the Central Bief concession and to acquire structural information on the mineralized trends through oriented core drilling in fresh rock. Five of the nine drill holes testing the Doyle 1, 2 and 3 prospect intersected gold mineralization in quartz veins with pyrite and tourmaline in shear zones hosted by mafic volcanic rocks (table B3). Visible gold was identified in hole CB-18-01A.
Table B3: Doyle prospect 2018 drilling results
This first limited drilling program confirmed the presence of significant gold mineralization in the northeastern corner of the Central Bief concession. Review of outcrop and core geology, together with previous and new structural data, enabled Reunion to frame the structural context of the area, contextualizing the known gold mineralization with the local structural geology. Steep shearing with its associated gold-bearing quartz veins is associated with the inverse flanks of folds. Plunge of the folds is gentle and either to the west-northwest or the east-southeast. Flat lying tension veins are associated with these high-strain zones. The drill intersections at Doyle, like in holes CB-18-01A and 03, are interpreted as being associated to tension veins.
In the last quarter of 2018 and first quarter of 2019, illegal artisanal miners discovered primary gold mineralization at the headwaters of a small creek on the south flank of a small hill at the center of an AEV held by CMB, which had previously finished mining alluvium in the area. The “garimpeiros” sunk shafts and adits and reportedly produced significant amounts of gold from the workings, but were eventually expelled by the French police.
In June 2019, Reunion geologists mapped the area and identified 47 shafts and adits scattered over an area of 260 m by 95 m elongated in an NNE-SSW direction (Figure SM 1). Systematic sampling of stockpiles of mineralized quartz vein material extracted and abandoned next to the shafts returned an average of 17.3 g/t gold from 42 samples with the highest assay at 45.9 g/t gold (Table 1). Stockpile masses vary from one hundred kilos to about 16 tons. Sampling of limited outcrop exposure returned assay results up to 18.2 g/t gold from a “grab” sample and up to 26.6 g/t gold over a one-meter channel sample. Reunion then covered an area 2x1.8 km with an induced polarization geophysical survey, including the entire area of artisanal workings, which coincide well with a north-south trending chargeability anomaly.
In September 2019, Reunion carried out an 18 hole, 900-meter reverse circulation (RC) drill program, followed by 1,000 m of diamond drilling across seven holes (Figure SM 1). These holes demonstrated that gold mineralization is hosted in saprolite of strongly sheared graphitic shale with boudinaged quartz veins and pyrite boxworks. Tables SM 1 and 2 show relevant intersections from diamond and RC drill holes (lower cut‐off at 0.4 g/t gold ‐ only intersections longer than 1.0 meter and grading above 1.0 g/t gold are included):
Figure SM 1: Schematic geological map of the St-Michel prospect area, showing location of artisanal shafts and Reunion drill holes.
Table SM 1: St-Michel prospect - Relevant intersections from diamond drill holes
Table SM 2: St-Michel prospect - relevant intersections from RC drill holes
Gold grades from drill holes are substantially lower than those obtained from quartz vein-only material of artisanal miners´ stockpiles, which essentially excluded host rock material. The mineralization trend remains open along strike and at depth and additional soil and IP chargeability anomalies are yet to be tested in the area. The presence of high-grade gold mineralization in the prospect is confirmed by an historical drill hole by Asarco which intercepted 1.5 m @ 22.2 g/t gold immediately to the southwest of the prospect in the 1990’s. Cyanidation recovery tests of stockpile samples indicated an average gold recovery of 94% after 24 hours of direct cyanide leaching, and 99% after 72 hours. In addition, a gravity recovery test gave a recovery of 65.1%.
The work done so far indicates that gold mineralization is hosted by graphitic shales and red siltstones from a distal turbidite sequence flanked by mafic volcanics, with a high density of boudinaged and tightly folded quartz veins associated with sulphides, along a northeast-striking subvertical trend interpreted as a shear zone. Additional studies are now underway to assess the structural control of gold mineralization along this shear zone.
Carapa prospect (STM)
Reunion re-logged and re-sampled historical core from the Carapa prospect, which was drilled by Iamgold in the 2000’s and known as St-Marie (STM). In total, Iamgold or previous titleholders had drilled over 5,500 m in the Carapa prospect area and identified gold bearing quartz/tourmaline-pyrite veins like those seen in the Doyle area.