Savannah Resources plc (LON:SAV), the AIM quoted resource development company, has today announced a maiden Mineral Resource Estimate of 3.2 million tonnes for the Reservatorio Deposit, which is one of three targets currently being advanced as part of the ongoing exploration and development programme for the Mina do Barroso Lithium Project (‘Mina do Barroso’ or the ‘Project’) in northern Portugal (Figure 1). Crucially further upside remains as the drill programme is ongoing, with the aim of further expanding the Reservatorio Mineral Resource and defining new JORC – 2012 compliant Mineral Resource Estimates at other deposits. To view the press release with the illustrative maps and diagrams please use the following link: Savannah PDF
HIGHLIGHTS:
· Initial Inferred Mineral Resource of 3.2Mt at 1.0% Li₂O containing 32,000t of Li₂O for Reservatorio Deposit
· Reservatorio is one of at least eight pegmatite deposits on the Mina do Barroso Mining Lease and one of three deposits currently being drilled
· Further drilling is now planned both down dip and targeting the potential eastern extension of the deposit where higher lithium grades occur
· Mineral Resource updates are likely for Reservatorio during 2018 as the drilling programme continues
· A maiden Mineral Resource Estimate for the Grandao deposit is expected during Q1 2018
· Drilling is ongoing and will take a short break over Christmas before commencing again in early January at which time a second rig will be introduced to accelerate the drilling programme
Savannah Resources Plc CEO, David Archer said: “That we have an estimated 3.2 million tonne Resource from just one of at least eight pegmatite deposits at our Mina do Barroso Lithium Project gives an indication of the potential scale of this project. We are now focused on defining a significant aggregate Mineral Resource from the multiple pegmatites that sit within the major lithium mineralised corridor that runs through our Mining Lease. The first to add to this aggregate Mineral Resource will be the high-grade (up to 2.1% Li₂O) Grandao deposit where we have completed extensive drilling and expect to deliver a Resource Estimate in the first quarter of 2018.
“The drilling results announced to date continue to underscore the potential of the Mina do Barroso Lithium Project to be a strategic upstream feature in the European lithium value chain. We believe Mina do Barroso is the closest European analogue to the very successful Australian hard-rock, open cut mine developments, which produce highly sought-after lithium spodumene concentrates for international markets. Our focus is therefore on rapidly advancing the project so that we can look to provide a European source of battery-grade lithium to supply the growing number of European battery manufacturers. With this in mind, we look forward to continuing to advance at pace our drilling and metallurgical test work programmes, which will be used to support an early scoping study around a potential mine development.”
Figure 1. Mina do Barroso Project Summary Map showing prospects and 2017 drilling
Mineral Resource Estimate
A Mineral Resource Estimate for the Reservatorio lithium deposit (Table 1-2 and Figures 2-4) has been completed by Payne Geological Services Pty. Ltd, an external and independent mining consultancy. The Reservatorio deposit forms part of Savannah’s Mina do Barroso project in northern Portugal. The deposit largely comprises a single, tabular pegmatite dyke with minor splays and the estimate is based entirely on results from 20 reverse circulation holes drilled by Savannah in 2017. The deposit outcrops over a strike length of approximately 500m and remains open, particularly at depth.
The Mineral Resource has been classified as Inferred Mineral Resource in accordance with the JORC Code, 2012 Edition.
Table 1. Reservatorio Deposit Inferred Mineral Resource Summary (above 0.5% Li2O cut-off grade)
Reservatorio Deposit |
Tonnes |
Li2O |
Fe2O3 |
Li2O |
Mt |
% |
% |
Tonnes |
|
3.2 |
1.00 |
1.4 |
32,000 |
Figure 2. Reservatorio Deposit – Geology and Drill Plan
Figure 3. Reservatorio Deposit – Mineral Estimate Model looking South
Figure 4. Reservatorio Deposit – Cross Section through the resource model
Table 2.
Reservatorio December 2017 Inferred Mineral Resource Estimate
0.5% Li2O Cut-off
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Bench |
Weathered |
Fresh |
Total |
||||||||||
Top |
Tonnes |
Li2O |
Ta2O5 |
Fe2O3 |
Tonnes |
Li2O |
Ta2O5 |
Fe2O3 |
Tonnes |
Li2O |
Ta2O5 |
Fe2O3 |
Li2O |
RL |
t |
% |
ppm |
% |
t |
% |
ppm |
% |
t |
% |
ppm |
% |
Tonnes |
610 |
1,000 |
1.20 |
21 |
1.4 |
|
|
|
|
1,000 |
1.20 |
21 |
1.4 |
|
600 |
87,000 |
1.06 |
19 |
1.3 |
7,000 |
1.38 |
15 |
1.5 |
94,000 |
1.09 |
18 |
1.3 |
1,000 |
590 |
97,000 |
1.03 |
20 |
1.3 |
124,000 |
1.19 |
21 |
1.4 |
221,000 |
1.12 |
20 |
1.3 |
2,500 |
580 |
19,000 |
0.88 |
17 |
1.2 |
284,000 |
1.12 |
20 |
1.4 |
303,000 |
1.11 |
20 |
1.4 |
3,400 |
570 |
5,000 |
0.96 |
20 |
1.5 |
381,000 |
1.04 |
18 |
1.4 |
387,000 |
1.04 |
18 |
1.4 |
4,000 |
560 |
24,000 |
0.95 |
18 |
1.4 |
485,000 |
1.01 |
16 |
1.4 |
509,000 |
1.00 |
16 |
1.4 |
5,100 |
550 |
15,000 |
0.80 |
14 |
1.3 |
495,000 |
1.00 |
17 |
1.4 |
510,000 |
0.99 |
17 |
1.4 |
5,100 |
540 |
1,000 |
0.83 |
14 |
1.5 |
415,000 |
0.97 |
16 |
1.4 |
417,000 |
0.97 |
16 |
1.4 |
4,100 |
530 |
|
|
|
|
361,000 |
0.96 |
15 |
1.4 |
361,000 |
0.96 |
15 |
1.4 |
3,500 |
520 |
|
|
|
|
208,000 |
0.91 |
15 |
1.3 |
208,000 |
0.91 |
15 |
1.3 |
1,900 |
510 |
|
|
|
|
119,000 |
0.85 |
14 |
1.3 |
119,000 |
0.85 |
14 |
1.3 |
1,000 |
500 |
|
|
|
|
54,000 |
0.88 |
14 |
1.3 |
54,000 |
0.88 |
14 |
1.3 |
500 |
490 |
|
|
|
|
7,000 |
0.93 |
14 |
1.3 |
7,000 |
0.93 |
14 |
1.3 |
100 |
Total |
250,000 |
1.01 |
19 |
1.3 |
2,940,000 |
1.00 |
17 |
1.4 |
3,190,000 |
1.00 |
17 |
1.4 |
32,000 |
Resource Summary – Reservatorio Lithium Deposit
Geology
At the Mina do Barroso Project, lithium mineralisation occurs predominantly in the form of spodumene-bearing pegmatites which are hosted in metapelitic and mica schists, and occasionally carbonate schists of upper Ordovician to lower Devonian age. The Reservatorio pegmatite is quite tabular and continuous and varies in thickness from 10m-30m. It strikes broadly NE-SW and dips to the NW at 25o to 40o.
Lithium is present in pegmatite bodies which are typically of aplite compositions and laboratory test work confirms that the lithium is almost exclusively within spodumene. Distinct lithium grade zonation occurs within the pegmatite, with weakly mineralised zones often evident at the margins of the dyke. Minor xenoliths and inliers of schist are observed on occasions.
The weathering profile comprises a shallow, surficial zone of weak to moderate oxidation, particularly of the schistose country rock. A zone of deeper weathering exists in the vicinity of an interpreted fault.
Drilling
A total of 20 reverse circulation (RC) holes define the Reservatorio Mineral Resource. The holes were drilled on an approximate grid spacing of 40m spaced holes on 80m spaced cross sections. All holes were drilled by Savannah in 2017 and all drill hole information and results have been previously reported to the market.
Drill collar locations are recorded in UTM coordinates using hand-held GPS, with elevations adjusted to a regional topographic DTM. All Savannah drilling has been down-hole surveyed using a gyroscopic tool.
Sampling and Sub-Sampling Techniques
For the Savannah drilling, a face-sampling hammer was used with samples collected at 1m intervals from pegmatite zones with composite sampling of typically 4m in the surrounding schists. The 1m samples were collected through a rig-mounted rotary splitter and were 4-6kg in weight. The 4m composites were collected by spear sampling of the 1m intervals. Samples were weighed to assess the sample recovery which was determined to be satisfactory.
Sample Analysis Method
For all Savannah drilling, whole samples were crushed then riffle split to produce a 250g split for pulverizing and analysis at the ALS Laboratories facility in Seville, Spain.
The samples were analysed using ALS laboratories ME-MS89L Super Trace method, which combines a sodium peroxide fusion with ICP-MS analysis. A multi-element suite is analysed.
QAQC protocols were in place for the drilling programs and included the used of standards, blanks and field duplicates. The data has confirmed the quality of the sampling and assaying for use in Mineral Resource estimation.
Estimation Methodology
For the Reservatorio Mineral Resource, a Surpac block model was constructed with block sizes of 40m (EW) by 10m (NS) by 5m (elevation) with sub-celling to 10m by 2.5m by 1.25m. The typical drill hole spacing is 80m (EW) by 40m (NS).
Interpretation of the pegmatite dykes was completed using detailed geological logging. Wireframes of the pegmatites were prepared and within those the sample data was extracted and analysed. A clear break in the grade distribution occurs at 0.5% Li2O and this grade threshold was used to prepare the internal grade domains for estimation.
Pegmatite and mineralisation domains were extrapolated up to 80m down-dip of the drill hole intersections and 40m along strike.
Sample data was composited into 1m intervals then block model grades estimated using inverse distance squared (ID2) grade interpolation. A first pass search range of 120m was used and oriented to match the dip and strike of the mineralisation. A minimum of 10 samples and a maximum of 24 samples were used to estimate each block. The majority of the resource (98%) was estimated in the first pass with an expanded search radius of 240m used for the few blocks not estimated in the first pass. No high-grade cuts were applied to the estimate.
Iron within the pegmatite is uniformly low, with a mean Fe2O3 grade of 1.4%. Other similar deposits have reported that a large proportion of the assayed iron is due to contamination from the abrasion of steel drilling and sample preparation equipment and this will be investigated as part of ongoing studies at the project.
No bulk density data is available for the deposit, so values were derived from similar deposits, which have been recently estimated. Bulk density values applied to the Reservatorio estimate were 2.2t/m3 for oxide lithologies, 2.6t/m3 for unoxidized pegmatite and 2.8t/m3 for unoxidized schist.
Mineral Resource Classification
The Mineral Resources was classified in accordance with the Australasian Code for the Reporting of Exploration Results, Mineral Resources and Ore Reserves (JORC, 2012).
The main pegmatite dyke at Reservatorio has been defined by 40m spaced drill holes on 80m spaced sections. The two easternmost sections are defined by single drill holes. Within the main pegmatite, the continuity of lithium mineralisation is good, however due to the broad drill hole spacing, the entire deposit has been classified as Inferred Mineral Resource.
The Mineral Resource has been reported to a depth of 130m vertical.
Cut-off Grades
The shallow, outcropping nature of the deposit and moderate to gentle dip suggests good potential for open pit mining if sufficient resources can be delineated to consider a mining operation. As such, the Mineral Resource has been reported at a 0.5% Li2O lower cut-off grade to reflect assumed exploitation by open pit mining.
Metallurgy
Metallurgical test work has been conducted by Savannah on representative mineralisation at the Mina Do Barroso project. The work was completed by Nagrom Metallurgical in Australia and confirmed that high grade lithium, low grade iron concentrate can be generated from the mineralisation using conventional processing technology. Microscopy confirmed that the concentrate was almost entirely spodumene.
Modifying Factors
No modifying factors were applied to the reported Mineral Resource estimate. Parameters reflecting mining dilution, ore loss and metallurgical recoveries will be considered during the any future mining evaluation of the project.
Preliminary Metallurgical Test Work (previously reported 26/06/17)
· Results from the preliminary ore characterisation metallurgical test work on a composite sample from Mina do Barroso to determine if the lithium bearing minerals can be recovered from the rock using commercially available technology and a saleable product produced have been received.
· Work confirms that a high grade very pure low iron spodumene concentrate can be produced from the Mina do Barroso lithium mineralisation.
· Single analysis of the combined sample confirmed a high Li2O head grade (~1.95% Li2O) and low Fe2O3 head grade (~0.9%)
· Heavy Liquid Separation (“HLS”) shows a very pure (~8%) Li2O product can be produced
· Flotation results utilising a simple one stage float without any optimisation achieved ~83.7% Li2O recovery at ~5.9% Li2O, this is very positive and can be improved through optimisation
· Microscopy confirmed that the concentrate was almost entirely spodumene with only very minor amounts of petalite
· Test work confirms that a high quality spodumene concentrate can be produced using conventional commercially available processing technologies.
Competent Person and Regulatory Information
The information in this report that relates to exploration results is based on, and fairly represents information and supporting documentation prepared by Mr Dale Ferguson, a Competent Person who is a member of The Australasian Institute of Mining and Metallurgy. Mr Ferguson is a director of Savannah Resource plc and has sufficient experience that is relevant to the style of mineralisation and type of deposit under consideration and to the activity being undertaken to qualify as a Competent Person as defined in the 2012 Edition of the “Australasian Code for Reporting of Exploration Results, Mineral Resource and Ore Reserves”. Mr Ferguson consents to the inclusion in this report of the matters based on his information in the form and context in which it appears.
The Information in this report that relates to Mineral Resources is based on information compiled by Mr Paul Payne, a Competent Person who is a Fellow of the Australasian Institute of Mining and Metallurgy. Mr Payne is a full-time employee of Payne Geological Services. Mr Payne has sufficient experience that is relevant to the style of mineralisation and type of deposit under consideration and to the activity being undertaken to qualify as a Competent Person as defined in the 2012 Edition of the “Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves”. Mr Payne consents to the inclusion in the report of the matters based on his information in the form and context in which it appears.