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Northern Silica Project

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Summary

Mine TypeOpen Pit
Study CompletedPreliminary Economic Assessment
Study in ProgressFeasibility
StagePermitting
Commodities
  • Silica
Mining Method
  • Truck & Shovel / Loader
  • Dry mining
Mine Life... Lock
SnapshotNorthern Silica Project is one of the world’s purest silica sand projects.

Mining and processing will be staged in two phases: an initial 3 Mtpa operation for the first two years using barge transhipment via existing port facilities, followed by a 5 Mtpa operation for the remaining 23 years with dedicated jetty infrastructure.

Various engineering studies and works were undertaken during 2024, focusing on supporting information required for the project's Environmental Impact Statement (EIS). These works included further refinement of the mining methodology and sequencing, final land forming, and reject sand management.

As at January 2025, Northern Silica Project’s EIS studies progress to final stages of impact assessment and mitigation following receipt of final Terms of Reference.

Diatreme targeting lodgement of draft EIS with Coordinator-General for adequacy check by late Q2, 2025, pending further consultation and engagement in first half.

Owners

SourceSource
CompanyInterestOwnership
Sibelco Silica Pty Ltd. 26.8 % Indirect
Diatreme Resources Ltd. (operator) 73.2 % Indirect
Diatreme Resources Limited holds 73.2% of the joint venture company Cape Silica Holdings Pty Ltd (CSHPL) and is the operator of the Northern Silica Project. Sibelco Silica Pty Ltd is a 26.8% joint venture partner in CSHPL.

Exploration Permits for Minerals 17795 is owned by Northern Silica Pty Ltd, subsidiary of the CSHPL. Exploration Permits for Minerals 27212 is owned by CCSHPL.

Deposit type

  • Sedimentary

Summary:

Silica sand mineralisation at Si2 Deposit occurs within the Cape Bedford / Cape Flattery Dune Field. The targeted silica sand deposits are the trailing arms and apex of elongate parabolic aeolian sand dunes.

The Cape Bedford / Cape Flattery Dune Field is one of several extensive areas of aeolian dunes which occur on the tropical east coast of Cape York Peninsula. The dune field covers an area of 700km2 and contains a variety of depositional and erosional landforms. The dominant source sand of the dune field is considered to be from the weathering of Mesozoic sandstone such as the Gilbert River Fm, and the Dalrymple Sandstone, however coastal granites and the Hodgkinson Fm are likely additional sources of sand.

As the Mesozoic sandstones are the aquifer units within the Laura Basin, they are likely to have been exposed to leaching while hosted within the sandstone, prior to exposure to erosional processes. Strong prevailing South-easterly winds appear to have been the consistent wind direction in the region, and still prevail today for most of the year. These winds are the energy source for the establishment and remobilisation of the sand dune systems.

The mineral resource is generally constrained to the trailing arms and apex of elongate parabolic dunes, which can be clearly defined using the surface LiDAR imaging. Drilling often intersects overlapped dunal features, which are not represented by LiDAR or aerial photography. Conversely, the interdunal areas are often devoid of thick aeolian sand and predominantly exhibit exposed B1 horizons, clays, bedrock, or other sediments. Where drilling has intersected obscured silica sand mineralisation, the sampled sand has been included in the geological model. There is an observable basement high on the topographic high towards the coastline on the western dunes.

The deposit style is an unlithified aeolian sand deposit, comprised of a series of complex parabolic and elongate parabolic dune systems repeatedly reworked and are superimposed upon older dune systems.

Geology
The Northern Silica Project is comprised of unlithified aeolian dune complexes. The Cape Flattery & Cape Bedford dune fields are aeolian dunes established in the Pleistocene epoch and regularly remobilised during the Pleistocene and Holocene epochs. The dune fields are situated on a coastal plain overlying the Hodgkinson Formation basement with Dalrymple Sandstone forming mesa on basement highs. Mineralisation is thought to be due to repeated eluviation and illuviation events on immobilised dune systems comprised of an existing quartzose sand source. Deleterious metals are thought to have been eluviated by organic acids, transported vertically down through the dunes and illuviated either by binding to clay rich horizons, or in the water table.

Mineralisation is unlithified quartzose sand.

Geological interpretation
Silica sand mineralisation at the Si2 Deposit occurs within the Cape Bedford / Cape Flattery Dune Field. The targeted silica sand deposits are the trailing arms and apex of elongate parabolic aeolian sand dunes. The mineral resource is generally constrained to the trailing arms and apex of elongate parabolic dunes, which can be clearly defined using the surface LiDAR imaging. Drilling often intersects overlapped dunal features, which are not represented by LiDAR or aerial photography.

Conversely, the interdunal areas are often devoid of thick aeolian sand and predominantly exhibit exposed B1 horizons, clays, bedrock, or other sediments. Where drilling has intersected obscured silica sand mineralisation, the sampled sand has been included in the geological model. There is an observable basement high coincident with the topographic high towards the coastline on the western dunes.

Dimensions
The Mineral Resource Estimate spans a total area of approximately 1270 hectares with varying dimensions: a maximum length along strike of 7.8 km and a width up to 2.7 km. The average thickness of the resource is 11.6 meters, though it can reach up to 55 meters. The top of the resource varies in elevation from 21.9mRL to 108.5 mRL, corresponding to the topography, while the bottom ranges from 16.9 mRL to 75.6 mRL, aligning with the water table or resource basement level.

Reserves

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Mining Methods

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Required Heavy Mobile Equipment

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Comminution

Crushers and Mills

Milling equipment has not been reported.

Processing

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Commodity Production

CommodityUnitsAvg. AnnualLOM
Silica dmt 5,000,000121,000,000
All production numbers are expressed as sand.

Operational metrics

Metrics
Annual ore mining rate  ....  Subscribe
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Annual processing capacity  ....  Subscribe
Ore tonnes mined, LOM  ....  Subscribe
* According to 2023 study.

Production Costs

CommodityUnitsAverage
All-in costs Silica AUD  ....  Subscribe
Assumed price Silica AUD  ....  Subscribe
* According to 2023 study / presentation.

Operating Costs

CurrencyAverage
Total operating costs ($/t milled) AUD  ....  Subscribe
* According to 2023 study.

Project Costs

MetricsUnitsLOM Total
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Expansion CapEx $M AUD  ......  Subscribe
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Total OpEx $M AUD  ......  Subscribe
Net revenue (LOM) $M AUD  ......  Subscribe
Pre-tax NPV @ 8% $M AUD  ......  Subscribe
After-tax NPV @ 8% $M AUD  ......  Subscribe
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Personnel

Mine Management

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Workforce

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