Base Resources: Toliara assays reveal further high-grade mineralisation
- 29,753m aircore drilling program from 770 holes completed over 2018 and 2019.
- Assay results received to date show material heavy mineral intercepts, particularly in the lower sand unit to the west of the current Ranobe Ore Reserves.
- Preliminary mineralogical assessment of two high grade lower sand unit intercepts show:
- Ilmenite, rutile and zircon make up approximately 50% of the HM and are in similar proportions to those reported in the existing Ranobe Ore Reserves estimate, with the remaining HM showing elevated levels of garnet.
- An increased proportion of higher value chloride ilmenite contained within the ilmenite.
- Ilmenite, rutile and zircon minerals appear to be of saleable quality.
- A further drilling program targeting the recently discovered high grade lower sand unit zones will be planned once the results of all existing drilling have been assessed.
All figures (graphics) referenced in this announcement have been omitted. Appendix 1 containing Tables 1, 2 and 3, which are referenced in this announcement and together contain details about all currently available assay results from the 2018-2019 drill program, has also been omitted from this announcement. A full PDF version of this announcement, including all figures (graphics) and Appendix 1 (containing Tables 1, 2 and 3), is available from the Company’s website: www.baseresources.com.au
Base Resources Limited (ASX & AIM: BSE) (Base Resources or the Company) is pleased to release initial assay results from recent drilling on the Ranobe mineral sands deposit in Madagascar.
The Toliara Project is based on the Ranobe deposit, located 45km north of Toliara in south-west Madagascar on a 125.4 km2 mining lease (Permis d’Exploitation 37242) (Refer to Figure 2 in the full PDF version of this announcement available from the Company’s website). The deposit comprises a single continuous body of mineralisation approximately 20km long, 1.5km to 5.5km wide and 3m to 100m in thickness and situated immediately west of a prominent north-south escarpment with mineralisation (including ilmenite, rutile and zircon) extending from the surface. The Ranobe deposit is host to the Ranobe Mineral Resources estimate (1.3 billion tonne @ 5.1% HM and 6.4% slimes) and the Ranobe Ore Reserves estimate (586 million tonne @ 6.5% HM and 3.9% slimes).
Over the course of 2018 and 2019, the Company completed 29,753m of drilling from 770 holes to test the extent of mineralisation to the west of the existing Ranobe Mineral Resources and at depth. While assaying is still ongoing, with only 67% of samples completed to date, results received show some material heavy mineral (HM) intercepts, particularly in the lower sand unit (LSU) to the west of the current Ranobe Ore Reserves.
Notable drill holes from the extensional drilling to the west of the current Ranobe Ore Reserves (all from surface) include:
- Hole R2076 – 81m @ 15.7% HM and 8.5% slimes, including LSU of 67.5m @ 18.3% HM and 9.3% slimes.
- Hole R2074 – 87m @ 13.9% HM and 5.1% slimes, including LSU of 69m @ 16.4% HM and 5.4% slimes.
- Hole R2084 – 71.5m @12.2% HM and 5.4% slimes, including LSU of 41.5m @ 17.6% HM and 6.7% slimes.
- Hole R1507A – 72m @11.6% HM and 8.2% slimes, including LSU of 43.5m @ 16.5% HM and 7.1% slimes.
- Hole R2022 – 87m @ 9.1% HM and 5.8% slimes, including LSU of 52.5m @ 13.8% HM and 7.3% slimes.
Refer to Tables 1 – 3 in Appendix 1 of the full PDF version of this announcement available from the Company’s website for a list of all currently available assay results from the 2018-19 drill program.
There are currently three recognised mineralised units at the Ranobe deposit: the upper sand unit (USU), which is the only unit within the current Ranobe Ore Reserves, the intermediate clay sand unit (ICSU) and the LSU, as illustrated in Figure 1 in the full PDF version of this announcement available from the Company’s website. Prior to Base Resources’ drilling, there were a limited number of intercepts of the ICSU and LSU and expanding the knowledge of these units was a key objective of the current drilling program.
The 2018-19 drilling program focused on the following areas:
- Western boundary extensional drilling (162 holes) to investigate the extent to which mineralisation continues to the west of the existing Ranobe Mineral Resources and at depth.Due to access limitations, drilling was limited to the northern half of the mining lease.Drill hole spacing in this area was predominantly 200m, and line spacings of 400m, 800m and 1,600m were used. 7,051 samples were collected, of which 87% have been assayed to date.
- Resource upgrade infill drilling (238 holes) within and around the inferred Ranobe Mineral Resources at the southern end of the deposit, aimed at improving confidence levels to measured or indicated and thereby allowing this area to be considered for inclusion in a future Ranobe Ore Reserves estimate update. In addition, the drilling investigated the lower mineralised units. Drill hole spacing in this area was predominantly 100m and line spacing is now infilled to 400m (from 1,600m). Of the 5,507 samples collected, 30% have been assayed to date.
- Mine planning infill drilling (370 holes) to provide greater definition within the existing Ranobe Ore Reserves for the first three years of mining and to also understand the extent of mineralisation in the lower units.Within the area of the first three years of mining the hole spacing is now 50m-100m and line spacing 100m.Of the 7,477 samples collected, 50% have been assayed to date.
The drill program commenced in 2018 and is ongoing, subject to drill rig availability, access and detailed assessment of all drill holes completed to date. Due to the significant scale of the drill program and associated bulk processing logistics, the majority of samples reported in this announcement were collated and exported from Madagascar in mid- 2019. As noted above, 67% of samples have been assayed to date – with all currently available assays reported in Tables 1-3 in Appendix 1 of the full PDF version of this announcement available from the Company’s website. Assaying of the samples will continue in 2020 and a further announcement will be made once the remaining results are available.
Exploration consisted of reverse circulation aircore holes drilled vertically with a 1.5m sampling interval and represent true width because the deposits zones are flat lying. The distribution of the drill holes is shown in Figures 3 and 4 in the full PDF version of this announcement available from the Company’s website as either coloured circles (where assays are complete), blue crosses (where assays are not complete) or orange crosses where there were no LSU assays or intercepts. The western boundary extensional drilling, which contains most of the significant intersects, covers an area 11km long and is up to 3km wide. The analysis of samples reported has been performed by Bureau Veritas in South Africa, who utilise a conventional mineral sand analytical procedure conforming to AS4350.2-1999 which reports percentages of heavy minerals, slimes (SL) and oversize (OS). No data aggregation was performed across drill holes, but the data presented in Tables 1-3 in Appendix 1 of the full PDF version of this announcement available from the Company’s website are length weighted averages for each mineralised zone in each drill hole drilled by Base Resources.
Bulk mineralogical assays are yet to be performed but a preliminary mineralogical assessment of two high grade LSU intercepts separated into three magnetic fractions using SEM by Process Mineralogy in Canada are positive. The magnetic fractions were also assayed by XRF. These assessments indicate ilmenite, rutile and zircon make up approximately 50% of the HM and are in similar proportions to those reported in the existing Ranobe Ore Reserves estimate, with the remaining HM showing elevated levels of garnet within the LSU compared to the USU (approximately 30-35% of HM compared to 1-5%). Additionally, there is some indication of increased levels of the higher value chloride ilmenite within the ilmenite. There was no indication of elevated deleterious oxides within the product minerals that might preclude or hinder their sale. The separability of the garnet and the opportunity to realise value from it will be assessed as part of any future feasibility studies.
Further work planned for 2020 includes:
- Results – completion of the outstanding assays for holes already drilled.
- Exploration – full assessment of all drilling results when available to guide a further drilling program, including targeting the recently discovered high grade LSU zones.
- Mineral Resources upgrade – progression of mineralogical estimates to allow an updated Mineral Resources estimate, focused on improving the confidence level of existing Mineral Resources from Inferred to Indicated in the area of the southern infill drilling.
Competent Person’s Statement
The information in this announcement that relates to Ranobe exploration results is based on, and fairly represents, information and supporting documentation prepared by Mr. Scott Carruthers. Mr. Carruthers is a member of the Australasian Institute of Mining and Metallurgy. Mr. Carruthers is employed by Base Resources, he holds equity securities in Base Resources, and is entitled to participate in Base Resources’ long-term incentive plan and receive equity securities under that plan. Details about that plan are included in the Company’s 2019 Annual Report. Mr. Carruthers has sufficient experience that is relevant to the style of mineralisation and type of deposit under consideration and to the activity which he is undertaking to qualify as a Competent Person as defined in the JORC Code and as a Qualified Person for the purposes of the AIM Rules for Companies. Mr. Carruthers has reviewed this announcement and consents to the inclusion in this announcement of the Ranobe exploration results and the supporting information in the form and context in which the relevant information appears.
For further information regarding the Ranobe Mineral Resources estimate refer to Appendix 3 below and Base Resources’ market announcement on 23 January 2019 “Updated Ranobe Deposit Mineral Resources (corrected)” available at https://www.baseresources.com.au/investor-centre/asx-releases/. For further information regarding the Ranobe Ore Reserves estimate refer to Appendix 3 below and Base Resources’ market announcement on 6 December 2019 “Maiden Ranobe Ore Reserves Estimate” available at https://www.baseresources.com.au/investor-centre/asx-releases/. Base Resources confirms that it is not aware of any new information or data that materially affects the information included in the 23 January 2019 and the 6 December 2019 market announcements and all material assumptions and technical parameters underpinning the estimates in those market announcements continue to apply and have not materially changed.
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