Axiom Mining Limited ('Axiom' or 'the Company') is pleased to announce an independent JORC (2012) Mineral Resource estimate on a small part of its Prospecting Licence 74/11 area (Kolosori tenement) of the Isabel Nickel Project, Solomon Islands.
Axiom CEO Mr Ryan Mount said, 'In the areas Axiom has drilled since November 2014, we've seen an increase in tonnage of 50% compared to the tonnage generated from historical information-it's encouraging that our maiden Mineral Resource estimate confirms our assumption that previous work has not tested the full laterite profile.'
The areas included in the Mineral Resource estimate are those closest to existing and planned site infrastructure.
'In the short term, this brings us closer to our goal of shipping ore by the end of 2015-it is also a milestone towards our strategic goal of having the first three to five years of production targets planned.
'We look forward to upgrading this initial estimate as drilling and resource definition progresses.'
This maiden JORC Mineral Resource estimate follows the successful completion of the orientation drilling program in June 2015 and Phase 1 of the resource definition drilling program in September 2015.
Modelling parameters and assumptions on density are relatively conservative reflecting the early stage of Mineral Resource estimation.
Axiom is now progressing to Phase 2 drilling that will step out from the existing drilling at the project's Kolosori tenement to define additional Resources.
This drilling is targeting mineralisation that has been indicated by historical INCO exploration.
The Mineral Resource is classified in accordance with the JORC (2012) guidelines with relevant details provided in this release and against the JORC (2012) Table 1 criteria (Sections 1 to 3) provided in Appendix A.
The Mineral Resource effective date is the 26 September 2015, the date of receipt of the last assay batch up to drill hole HA-719, and is based on 542 Axiom drill holes with 6864 m of core samples and 7859 assayed intervals.
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Measured 0.9 Mt @ 1.1% Ni, 0.12% Co
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Indicated 1.0 Mt @ 1.0% Ni, 0.11% Co
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Inferred 1.0 Mt @ 1.0% Ni, 0.11% Co
Total 2.9 Mt @ 1.1% Ni, 0.11% Co
The total saprolite (magnesium silicate) Mineral Resource at a 1.0% Ni cut-off is:
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Measured 0.9 Mt @ 1.8% Ni, 0.03% Co
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Indicated 0.6 Mt @ 1.6% Ni, 0.03% Co
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Inferred 0.5 Mt @ 1.6% Ni, 0.03% Co
Total 2.0 Mt @ 1.7% Ni, 0.03% Co
The combined total laterite Mineral Resource at a 0.7% or 1.0% Ni cut-off is:
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Measured 1.8 Mt @ 1.4% Ni, 0.07% Co
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Indicated 1.6 Mt @ 1.3% Ni, 0.08% Co
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Inferred 1.5 Mt @ 1.2% Ni, 0.08% Co
Total 4.8 Mt @ 1.3% Ni, 0.08% Co
Direct shipping of ore (DSO) operations will generally require higher nickel grades for development.
To provide additional information on potential ore products, Table 1 shows the breakdown of the total Mineral Resources under the following categories:
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Low grade limonite
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between 0.7% to 0.9% Ni
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Medium grade limonite
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between 0.9% to 1.3% Ni
|
|
High grade limonite
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>1.3% Ni
|
|
Low grade saprolite
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between 1.0% to 1.3% Ni
|
|
Medium grade saprolite
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between 1.3% to 1.6% Ni
|
|
High grade saprolite
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>1.6% Ni
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While some blending would be required, the following groups provide an indication of the potential DSO products and will be reviewed in the upcoming scoping study and mining assessments:
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HGS for pyro-metallurgical smelter feed
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HGL and MGS for Carron process feed
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MGL for HPAL feed
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LGL and MGL for NPI feed.
Table 1 Total Mineral Resource by potential product categories
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Classification
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Category
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Mt
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Ni %
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Co %
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Fe2O3 %
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MgO %
|
SiO2 %
|
DBD
|
|
Measured
|
LGL
|
0.21
|
0.83
|
0.11
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69.2
|
1.2
|
2.8
|
1.30
|
|
MGL
|
0.53
|
1.06
|
0.12
|
67.5
|
1.6
|
4.1
|
1.20
|
|
HGL
|
0.18
|
1.63
|
0.10
|
54.2
|
5.8
|
15.9
|
0.95
|
|
LGS
|
0.05
|
1.21
|
0.02
|
16.7
|
26.7
|
40.1
|
1.15
|
|
MGS
|
0.22
|
1.47
|
0.02
|
17.3
|
26.2
|
39.7
|
1.15
|
|
HGS
|
0.60
|
1.93
|
0.03
|
19.7
|
24.1
|
38.5
|
1.00
|
|
Indicated
|
LGL
|
0.27
|
0.84
|
0.10
|
67.1
|
1.5
|
3.3
|
1.29
|
|
MGL
|
0.62
|
1.05
|
0.11
|
66.5
|
1.8
|
4.3
|
1.20
|
|
HGL
|
0.11
|
1.51
|
0.10
|
56.2
|
5.6
|
13.5
|
0.95
|
|
LGS
|
0.08
|
1.21
|
0.03
|
20.3
|
25.6
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36.6
|
1.15
|
|
MGS
|
0.20
|
1.45
|
0.03
|
20.5
|
25.0
|
36.7
|
1.15
|
|
HGS
|
0.30
|
1.85
|
0.03
|
21.1
|
23.5
|
37.5
|
1.00
|
|
Inferred
|
LGL
|
0.19
|
0.83
|
0.11
|
64.5
|
2.6
|
4.8
|
1.23
|
|
MGL
|
0.70
|
1.04
|
0.11
|
65.5
|
1.9
|
4.4
|
1.20
|
|
HGL
|
0.07
|
1.53
|
0.09
|
50.0
|
7.6
|
14.9
|
0.92
|
|
LGS
|
0.06
|
1.22
|
0.03
|
19.6
|
25.1
|
35.7
|
1.15
|
|
MGS
|
0.27
|
1.46
|
0.03
|
20.7
|
24.4
|
36.4
|
1.15
|
|
HGS
|
0.19
|
1.79
|
0.03
|
21.1
|
23.4
|
37.4
|
1.00
|
|
Total
|
LGL
|
0.67
|
0.83
|
0.10
|
67.1
|
1.7
|
3.6
|
1.27
|
|
MGL
|
1.84
|
1.05
|
0.12
|
66.4
|
1.8
|
4.3
|
1.20
|
|
HGL
|
0.36
|
1.57
|
0.10
|
54.0
|
6.1
|
15.0
|
0.94
|
|
LGS
|
0.18
|
1.21
|
0.03
|
19.2
|
25.7
|
37.2
|
1.15
|
|
MGS
|
0.69
|
1.46
|
0.03
|
19.6
|
25.2
|
37.5
|
1.15
|
|
HGS
|
1.09
|
1.89
|
0.03
|
20.3
|
23.8
|
38.0
|
1.00
|
DBD = dry bulk density t/m3
Location
Santa Isabel Island is situated 135 km north-west of the capital Honiara and accessible by air or sea (Figure 1). Axiom's Kolosori tenement is located with 12 degrees off the equator and more than 1500 km from the nearest continent.
Solomon Islands experiences a tropical environment, characterised by high and relatively uniform temperatures and humidity throughout the year and relatively high annual rainfalls.
Figure 1 Isabel Nickel Project location
Tenure
Axiom holds Prospecting Licence PL 74/11 (Kolosori tenement) on Santa Isabel Island (Figure 2), which is 80% held by Axiom with the remaining 20% held by local landowners-the same ownership structure applies to the Prospecting Licence PL01/15 (South San Jorge tenement) on nearby San Jorge Island.
The deposits drilled and defined by Axiom are wholly contained within the Kolosori tenement on Santa Isabel Island.
Both areas at Santa Isabel and San Jorge were explored extensively by INCO in the 1960s and 1970s using test pitting, drilling and auger sampling methods to define nickel laterite deposits of potential economic interest.
INCO completed some feasibility studies in the late 1960s and further feasibility studies and metallurgical test work were completed in the 1990s by Kaiser Engineering.
Figure 2 Tenure and project overview (see Figures 6 and 7 for more detail)
Geology
The Solomon Islands archipelago is located at the boundary of the Australian and Pacific continental plates, with Santa Isabel and San Jorge Islands part of a linear NW-SE trending chain of islands within the New Georgia Group and adjacent to an active volcanic forearc region.
Continental collision has resulted in the uplift and obduction of sea floor sediments including some limestone and mostly volcaniclastic sediments-this has included overthrusting of ultramafic rocks that now form elongate pods of more or less serpentinised harzburgite and dunite, cut by pyroxenite veins.
The nickel laterite deposits of Solomon Islands have developed under tropical conditions over ultramafic rocks (Figure 3). Their formation is largely by weathering and decomposition of the ultramafic host rocks which leads to residual and supergene enrichment of nickel within the laterite profile.
The laterite formation wraps over the topography and comprises two principal zones overlying fresh and weathered rock that include:
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the saprolite zone where weathered silicate minerals remain. This zone can include weathered to fresh remnant rocks and silicate clay minerals from the initial decomposition and weathering of the host ultramafic rocks. Residual enrichment is limited and nickel is generally enriched within the saprolite by supergene processes.
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the limonite zone where silicate minerals are largely destroyed and removed leaving dominantly the iron rich oxides such as limonite (goethite) that can grade into higher alumina oxide mineral towards surface. Residual enrichment of iron, aluminium, manganese, cobalt and nickel occur from the compaction of the profile from the intense leaching from tropical rainfall over time.
The intense serpentinisation of the ultramafics has resulted in thin but consistent laterite profiles developed on ridge slopes at Santa Isabel and more rounded hill tops at San Jorge, which has less precipitous terrain.
Figure 3 Local geology-map derived from government geological mapping
Drilling and sampling
In the 1960s, INCO completed extensive sampling over the Isabel tenement area, mostly by test pits (shafts) and channel sampling on 200 m centres. Analysis was limited to Ni, Co and Fe assaying and survey discrepancies locating the old pit sites are up to 40 m.
Axiom used these data to target initial exploration but not to inform the current resource statement.
Since gaining access to the sites Axiom has undertaken two stages of drilling-orientation drilling and resource definition drilling (Figure 2).
Orientation drilling took place from November 2014 to June 2015 for 133 drill holes and 1865 m was completed by a single diamond drill rig. This was used for initial orientation drilling at Havihua and Kolosori Ridges and completed all current drilling at Suma Ridge.
Orientation drilling predominantly used HQ diamond core but included PQ and NQ core. Half core sampling was undertaken on initially regular 0.5 m intervals changing to regular 1 m intervals towards the end of the program, with some sub-sampling on smaller lengths on geological contacts.
Phase 1 of resource definition drilling was undertaken from July 2015 to September 2015 for 409 drill holes and 5001 m was completed by up to six man-portable custom-build drill rigs. The program included largely 25 m grid drilling of mineralisation identified at Havihua and Kolosori Ridges.
Resource definition drilling was NQ core using a tungsten bit. Core sampling was generally whole core sampled on regular 1 m down hole intervals with sub sampling down to 0.3 m on significant geology contacts. Half core sampling was used for holes selected for QAQC duplicate sampling.
Analysis
All Axiom samples were dispatched to Honiara and prepared in a commercial preparation facility run by Intertek Genalysis Laboratory Services (Intertek).
Sample preparation was by normal methods and included drying (24 hrs at 90ºC), crushing to 5 mm, splitting to ~1.4 kg, pulverisation to 90% passing 200 mesh. 50 g pulps were dispatched to Intertek Laboratories in Australia for analysis by glass fusion XRF for a standard 12 element nickel laterite suite, method FB1/XRF, that included Ni, Co, Fe, Si, Mg, Al, Ca, Cr, Mn, Cu, K, Na, P, S, Ti and Zn.
In addition, loss on ignition was also undertaken using thermos-gravimetric analysis.
Initial batches were also assayed by ICP method 4A/OE for verification of the XRF results but are not otherwise reported or used in the estimate.
Estimation
The laterite profile in each drill hole was interpreted to define five sequential domains using geochemistry and logging. The domains capture the critical changes in mineralisation enrichment and other material type changes and include:
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an upper overburden zone of the limonite with minimal nickel enrichment
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limonite zone with nickel and cobalt enrichment comprising iron rich oxides
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transition zone comprising either mixed limonite/saprolite samples or transitional clays when present
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saprolite zone with nickel enrichment comprising weathered silicate mineral
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bedrock or rock saprolite with minimal to no nickel enrichment.
Sharp or rapid changes in grade across each domain boundary warrant domaining and independent estimation. The domains were wireframed in conjunction with an extrapolation boundary as a conservative thinning edge model with the boundaries presented in Figure 2.
The boundary was based on the outermost sampling information that included both Axiom and INCO sampling information and interpretation of any limitations evident in the topography data.
Resources are only reported to maximum extrapolation of 50 m from the last available Axiom drill hole.
A block model was constructed with from 10 m by 10 m by 1 m flat blocks to represent the domains. Block elevations were calculated in true space, flattened to the down hole depth and unfolded to the top or bottom of each domain. The unfolded coordinates were used for estimation using Ordinary Krigeing of each domain and variogram models derived for that domain.
The flattened coordinates were used to assist the visualisation and manual verification of the model estimates. Examples of the domain and grade estimates in flattened spaced are provided in Figures 4a-4e and the resulting nickel estimates in true space in Figure 5.
Figure 4a Kolosori 9066150 mN displaying flattened block model section - Domain
Figure 4b Kolosori 9066150 mN displaying flattened block model section - Ni%
Figure 4c Kolosori 9066150 mN displaying flattened block model section - Co%
Figure 4d Kolosori 9066150 mN displaying flattened block model section - Fe2O3%
Figure 4e Kolosori 9066150 mN displaying flattened block model section - MgO%
Note: No vertical exaggeration
Figure 5 Kolosori 9066150 mN displaying true space block model Ni section
Resource comparison
Only part of the area pitted and estimated by INCO has been drilled by Axiom.
Hence it is not possible to directly compare the current estimates to the original 1960s resource estimates by INCO. Using only the INCO pit data, the current resource estimation method results in similar global low and high grade estimates.
Comparing these INCO data estimates to the current Axiom drilling estimates for the same area provides the following comparison:
-
Similar tonnage of low grade limonite with 5% less Ni grade and 15% more Co grade. These grade differences are due to suspected assay biases in high iron samples in the INCO pit sampling, which were not uncommon in the 1960s.
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Less high grade limonite due to the lower overall grade in Ni.
-
Significant increase in low and high grade saprolite (80%) that can be attributed to:
-
thicker over depth of saprolite as the INCO pits did not test the full profile in all cases
-
additional high grade saprolite defined at specifically Kolosori, largely between previous 100 m INCO pits
-
a higher proportion of high grade is defined when in-fill drilled due to the reduction of the smoothing effect present with broad spaced drilling.
The last point has implications for the current Inferred Mineral Classified areas that are also defined at 50 to 100 m spacing and could be expected to underestimate the proportion of high grade saprolite resource though still be indicative of the global laterite resource.
Classification
Resource classification adopted a typical industry approach for wet tropic laterites using drill spacing, this is supported by the variogram analysis.
Polygons displayed in Figure 6 and Figure 7 were applied to the block model on the basis of:
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25 m spacing and 12.5 m extrapolation for Measured Mineral Resource
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50 m spacing and 25 m extrapolation for Indicated Mineral Resource
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100 m spacing and 50 m extrapolation for Inferred Mineral Resource.