The Muchea West Silica Project, acquired by Carbine Resources in July 2021, is located less than a kilometre from the town of Muchea, 40 km north of Perth, adjacent to both the Moora-Kwinana rail line and the Brand Highway. The northern extension of the Muchea West sand dune is host to the VRX Resources, Reserve and silica sand Mining Lease.
Drilling completed in 2019 and 2021 has identified high purity silica sands at Muchea West with over 99.5% SiO2 and low levels of impurity (Fe2O3 and Al2O3). The grade of the silica sand exceeds the requirements for Float and Container glass. This unusually high grade can result, following a simple processing route, in a number of products at the premium end of the silica glass market including the ultra clear, high-tech glass market.
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Muchea West Silica Sand Project
The region surrounding the Project has been explored for both silica sand and mineral sands.
A total of 82 vacuum drill holes (78 drill holes to a depth of 10m and 4 drill holes to depths between 15m and 20m) were drilled at nominal 200m spacing on six drill lines along existing tracks (as shown in Figure 3 below) within the tenement area. This drilling was completed by Australian United Silica Corporation Pty Ltd (Ausco). Previously the area within the tenement has been drilled for water and this drilling resulted in 28 water bores.
Figure 1: Location Plan
Current Exploration Activities
Carbine’s maiden drill program consisted of a total of 233 vacuum drill holes which were drilled at nominal 50m spacing on five drill lines along existing tracks (as shown in Figure 2 below) within the tenement area. This drilling was completed by Strataprobe Pty Ltd.
Figure 2: Drill Collar Plan
The drilling encountered unconsolidated sand and was terminated either at designated depth or the water table. The water table was in most places higher than expected due to the exceptional rainfall in the preceding two years. For the vacuum drilling, 1 metre downhole samples were collected at each drilling location. Vacuum drill samples are collected in a plastic tube and riffle split into two sample bags. One of the samples is prepared for laboratory and the other is retained for repeat analysis, process studies and QA/QC purposes. The sample splitter and vacuum tube are cleaned regularly to prevent sample contamination.
Figure 3: Vacuum drilling line 5
Drilled samples for each 1 m interval were also placed into chip trays which were photographed to provide a permanent record of the downhole lithology. Detailed visual assessment and logging of sample recovery are provided in the drill logs. The first metre of all the drill holes is mainly the humus layer and, as such, not assayed.
Major and trace elements in exception to SiO2 were analysed using a four-acid digest followed by Inductively Coupled Plasma Optical (Atomic) Emission Spectrometry (ICP-OES) analysis. Loss on Ignition (LOI) at 10000C was analysed by Thermal Gravimetric Analyser. SiO2 was back calculated by subtracting all ICP major and trace elements plus LOI from 100%.
A total of 1,088 samples have been transported to Intertek Genalysis Laboratories, with results expected in January 2022.
The Muchea West drillhole database consists of 315 drill holes for a total of 2,737m. The drilling is all Aircore (Vacuum) and has been located on existing, cleared tracks avoiding the need for clearing of the native vegetation and minimising any potential spread of jarrah dieback.
Maiden Mineral Resource Estimate
Assay and lithological data from these 315 drill holes were used to interpret the base and top of the silica sand horizon as presented in the drilling data. These define the Main Sand horizon. A surface has also been generated at 3m above the modelled 2019 water table, representing the likely true base of the silica sand; this zone, below the Main Sand horizon is coded as the Lower Sand.
These surfaces have been used to constrain a block model of silica grades using an Ordinary Kriging interpolation methodology.
The Muchea West Silica Sand Mineral Resource has been classified in the Indicated and Inferred categories, in accordance with the 2012 Australasian Code for Reporting of Mineral Resources and Ore Reserves (JORC Code) and has been reported at a 99.00 % SiO2 cutoff.
Logging data from an additional 28 water bores (for a total of 1,315m) was also used as an aid to interpretation. No grade data from the water bores was used.
Table 1: Muchea West Silica Sand Project – Mineral Resource Estimate – All Drilling
|Main + Lower||Indicated||99.00||25.90||39.89||1.54||99.73||0.034||0.025||0.003||0.052||0.135|
|Main + Lower||Inferred||99.00||34.60||53.28||1.54||99.70||0.052||0.026||0.005||0.056||0.147|
|Main + Lower||Total||99.00||60.50||93.17||1.54||99.71||0.044||0.026||0.004||0.054||0.142|
(For details refer to full report: Carbine Resources Muchea Silica Sand Project Report May 2022)
South East Resource
The South East Area of Interest at the deposit will be a focus for the Company to convert it to the initial mining area, and has a separate high-grade resource reported. The unclassified material in the block model has been extended in this area (see Figure 4) and has been reported as an Exploration Target reflecting the greater confidence related to this material.
Samples from this drilling have been used to compile a bulk sample that is representative of the characteristics of the silica sand in the drilling that produced the Resource Estimate. The bulk sample is the feed for a series of Scoping Studies that are underway and should result in a proposed flow sheet and final product characteristics.
Figure 4: South East Area Sand Resource Classification
Table 2: Main + Lower Sand– Indicated and Inferred Resource – SE Drilling Only
Revised Exploration Target
The Mineral Resource Estimate is defined from within the maiden Exploration Target reported to the ASX on 29 July 2021 and has the affect of removing that area from the Exploration Target and upgrading it to a Resource. Subsequently the Exploration Target is reduced.
The subsetting of the South East Resource and the South East Exploration Target changes the reporting of the Exploration Target.
In addition to the maiden Resource of 93 Mt @ 99.7% SiO2, the Exploration Target for the Muchea West Silica Sand Project is now reported as:
- Western Area: 400Mt to 500 Mt of Silica Sand at an average grade of 99.6% to 99.8 % SiO2
- Eastern Area: 210Mt to 270 Mt of Silica Sand at an average grade of 99.6% to 99.8 % SiO2
- South Eastern Area 152 Mt to 168 Mt of Silica Sand at an average grade of 99.6% to 99.8% SiO2
The potential quantity and grade of the Exploration Targets are conceptual in nature. There has been insufficient exploration to estimate further Mineral Resources and it is uncertain if further exploration will result in the estimation of additional Mineral Resources.
Following the receipt of the final assays in March 2022, a representative bulk sample was compiled from selected samples (different holes and different depths) spaced across the south east drill lines 1 and 2. The samples were taken from both the 2019 drill program and the 2021 drill program.
This bulk sample was delivered to Independent Metallurgical Operations Pty Ltd (IMO) and will be utilised in the testwork required to refine the proposed process flowsheet and deliver processed material that will be used in any future offtake discussions regarding silica sand products from the Muchea West Project. IMO will produce a costed flowsheet and operating parameters that will be fed into a financial model for the assessment of the project.
IMO have engaged Orelogy Pty Ltd to undertake the mining, transport and port components of the study.
Financial modelling will result from this Scoping Study and this information will then be used to design the model of a Feasibility Study.
The initial fauna studies have been completed but this is an ongoing study and is not anticipated to be reported until H2 2022. The final botanical study has been deferred at this time until spring 2022 to complete the requirements for a proposed Mining Licence Application.
These surveys will form the data package to support for the lodging of a Mining Licence Application (MLA) with the Department of Mines, Industry Regulation and Safety (DMIRS).
Early rains means that Carbine cannot access the Muchea West Project during the 2022 winter to avoid the spread of jarrah dieback and comply with tenement conditions.