Embracing the cyclical nature of the mining sector
Projects & Royalties
2.5 % NSR
LGN Holdings (BVI) Inc.
Shear-hosted gold (Birimian greenstone belts)
Within the same belt as the 7.0 Moz Morila Au mine
1.02 Moz Au (Ind+Inf)
Next Phase of Work:
Marvel Gold Limited (ASX:MVL)
US$1.45M in milestone payments + 2.5 % NSR
The 100km2 Tabakorole Project is situated in South Western Mali, 280km from Bamako and 17km South of the village of Garalo. Tabakorole hosts a resource (calculated at a 0.6g/t Au cut off grade) of 1,025,000 ounces contained Au for 1.2 g/t Au, comprised 360,000 ounces at 1.2g/t Au in the 'indicated' category and 665,000 ounces at 1.2g/t Au in the 'inferred' category from the oxide and fresh zones (Table 1). The mineral resource estimate was prepared in accordance with the JORC Code and was commissioned by the Company's joint venture partner, Marvel Gold Limited (https://marvelgold.com.au/) and reported as at 5th October 2020. Drilling results include 44m @ 3.29g/t Au and 16m at 9.31g/t Au (Table 2). The FT Prospect remains open along strike and down dip.
A number of targets have been defined for follow up exploration with potential for resource expansion, notably recent air-core (‘’AC’’) and diamond (‘’DD’’) drilling has confirmed that gold mineralisation continues at least 600m to the north-west along strike of the FT Prospect, which remains open along strike and at depth. There are also areas throughout the existing resource that are constrained due to a lack of drilling data as well as a new lode discovered and included in the current mineral resource estimate. This new new lode has been modelled to a length of ~120 m and to a maximum depth of 12 0 m and remains open at depth and along strike.
Additional targets include the 2.5km long FT South target, a geophysical anomaly sub-parallel to the FT prospect historic resource, and the FT East target, defined by a 2.6km long gold in soil anomaly. Drilling undertaken after the historic resource in 2010, 2011 and 2014 returned results including 18m@ 6.05g/t Au and 24 m at 2.53 g/t Au were not followed up by the previous operator.
The shear zone, up to 200m wide, is part of the Massagui Belt which hosts Barrick Gold's (NYSE : GOLD) Morila gold mine (6.0Moz Au).
Table 1: Tabakarole project JORC compliant mineral resource (2020)
Grade (g/t Au)
Metal (Oz Au)
Table 2: Selected Tabakorole drill intersections
Grade (g/t Au)
Intersections based on 0.5g/t Au cut off and ⩽ 2m non-cumulative internal waste
A major Au soil anomaly was delineated from results of a regional soil sampling programme with grid spacing of 500m x 100m following initial discover by BHP in the early 1990s during a regional soil sampling programme. Since 2003, 28,912m of diamond, 31,943m of RC, 6,577m of auger and 60,676m of air core drilling have been completed along with 1,400km of airborne geophysics.
In 2014, Legend completed a 741 m infill RC drilling programme. The 14 drill holes were positioned to provide intersections in oxide mineralisation in areas where sulfide grades had been extrapolated into the oxide zone. The drilling confirmed continuity and grade of oxide mineralization of the FT deposit. Later in 2014 a detailed and infill termite mound sampling programme on an area of approximately 3km by 2km on the Npanyala exploration permit was also completed.
During 2020, under joint venture, 520 line kilometres of ground magnetics have been completed, covering the north of the licence with 9 priority magnetic anomalies identified with a combined strike length of over 8km. 2,042m of AC drilling were completed in Q2 2020 with down the hole intercepts including 1.05g/t Au over 12m from 9m, 0.77g/t Au over 21m from surface and 6.2g/t Au over 6m from 14m depth defining a 600m northwest extension to the FT Prospect. Results from an eight-hole, 1,544m, diamond drill programme, completed in August 2020 focussed on infill drilling along the FT Prospect, with down the results returning 4.7g/t Au over 14m and 1.2g/t Au over 31m.
During 2021, under joint veture, a preliminary program of metallurgical test work was completed on four fresh rock composite samples collected from four diamond drillholes completed by Marvel in mid-2020. The composites were made from the coarse split of diamond drilling samples based on the drillhole locations within the deposit and the head grade assay of the original samples. The composites targeted the current Mineral Resource grade of 1.2g/t Au and ranged from 1.1 to 1.9g/t Au. Results from the bottle roll testwork showed high recoveries from all samples with low cyanide and lime consumption with average leach recoveries of 92.7%, 94.8% and 96.9% at three grind sizes of 75um, 106um and 150um. The high recoveries indicate gold is likely to be recoverable via a simple carbon-in-leach process flow sheet, with no indications of refractory gold. Furthermore, Marvel completed approximately 9,000 m of drilling including approximately 5,150m AC, 2,280 m RC, 4,320 m DD and 250 m of RC-DD holes. Results include 2.1g/t Au over 12m, 1.8g/t Au over 29m from RC holes and 2.4g/t Au over 24m and 1.5g/t Au over 26m from DD holes.
Mineral Resource Estimate
International Resource Solutions Pty Ltd of Perth, Australia, prepared the MRE in accordance with JORC Code as detailed in Table 2 below.
Table 2: Tabakorole Mineral Resource Grade-Tonnage
Cutoff (Au g/t)
Multiple Indicator Kriging (“MIK”) with change of support was selected as the most appropriate method for estimating the gold resource contained in the Tabakorole deposit. A total of two grade estimate domains have been developed within the mineralised zones and based on the geological description in the previous sections and an approximate lower cut-off grade of 0.3 g/t gold.
A block size of 20mE x 25mN x 10mRL was selected as an appropriate block size for estimation based on the drill spacing (50m strike spacing or better), the geometry of mineralisation and the likely potential future selective mining unit (SMU) (appropriate for potential open-pit mining). An SMU dimension of 5mE x 12.5mN x 5mRL was selected as appropriate for support correction investigation. An indirect lognormal support correction was applied to emulate mining selectivity for the above SMU dimension.
The MIK grade estimates consist of a series of proportions and grades above the pre-defined cut-off grades estimated into a ‘panel’ or large blocks. The proportions and grades are derived from a targeted SMU block size via change of support process. As such, while the proportions and grades at a certain cut-off for any given panel may be known, its position within the panel is not. To assist with a more intuitive presentation of the model grades, the MIK grade estimates have been localised to SMU dimension blocks using a process identical to that of Localised Uniform Conditioning. The SMU sized blocks have been assigned a single grade so that the panel MIK grade estimate grade tonnage curve has been replicated.
Raw sample intervals from the drill hole database were flagged by the estimation domains and composited to 2m downhole intervals for the purposes of equalising sample support and as an input to grade estimation.
The impact of higher-grade gold outliers was examined on composite data using log probability plots and cumulative statistics. This is particularly relevant in the case where extreme grade values may exist however MIK estimation as implemented at Tabakorole is independent of top cutting and was therefore not applied to the final grade estimate.
Grade and indicator variography were developed based on the downhole composites. Indicator variography was input to the MIK estimates while grade variography was used for the change of support analysis applied to the MIK estimates.
The proposed development scenario for the deposit is as an open cut (pit) mine. No additional mining dilution has been applied to the reported MRE.
Limited metallurgical test work has been completed on oxide material. The test work was carried out by Peacocke and Simpson in Zimbabwe in October 2015 on a 100kg sample collected using auger drilling over an area of 20 x 25m centred around hole 06TKDDH-059. The process yielded a total of 90.6% recovery using a conventional cyanidation process. Due to the limited coverage and selective nature of sampling the results from this test work are not considered representative of the deposit. Marvel completed a preliminary program of metallurgical test work with four fresh rock composite samples were collected from four diamond drillholes completed by Marvel in mid-2020 targeting the current Mineral Resource grade of 1.2 g/t gold. Results from the bottle roll testing showed high recoveries of 92.7%, 94.8% and 96.6% at three grind sizes indicating gold is likely to be recoverable via a simple carbon-in-leach process flow sheet.
Resource classification was based on geological confidence and a spatial review of estimation result parameters which reflected the quality of the estimate for each block. At the Tabakarole deposit, areas that had high confidence estimate values, had sufficient drilling density (≤50m section spaced drilling) or were proximal to 50m spaced drill lines were classified as Indicated Resources. The remainder was classified as Inferred.