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Geology and Mineralisation

Different Types of Ilmenite Mines

The vast majority of ilmenite are produced from heavy mineral (HM) rich sand mines, such as Moma in Mozambique and Kwale in Kenya, and titanium-rich igneous and metamorphic hard-rock mines, like Tellnes in Norway and Panzihua in Sichuan China. 


Our Roper River Ilmenite Mine is different and unique as ore is expressed as reddish and brownish soils ("regolith" in the technical term). 


The major characteristics of the three types of ilmenite mines are summarised below.    

Type I: Hard Rock

Ore is formed by igneous/volcanic rocks


  • Tellnes in Norway

  • Panzihuan in China

  • RTFT in Canada



  • Can have high Titanium Content

  • Can be large in quantities

  • Co-produced with Iron product, and may help economics when Iron price is high


  • Titanium content highly heterogeneous

  • Require crushing and complex processing to separate

  • Normally co-produced with Iron, so production can be impacted by Iron price

Type II: Mineral Sands

Ore is formed by beach sands or eolian sands


  • Richard Bay Mine in South Africa

  • Moma in Mozambique

  • Kwale in Kenya



  • Shallow_ mostly formed by ancient/present beach/eolian sand dunes

  • Simple separation process for HM

  • Can have multiple valuable heavy minerals (including ilmenite, zircon, rutile, etc)


  • Different separation methods are required for separating VHM

  • Resource quantity is variable and sand bodies varies in geometry and size

Type III: Regolith

Ore is laterite soil

Roper River (A.I.R) 



  • Shallow and flat_ formed by in-situ weathering and alteration of bedrocks

  • Heavy mineral dominated by ilmenite, with minor magnetite 

  • Simple separation process


  • Lack other VHM, etc., rutile and zircon

  • High slimes content (de-sliming treatment needed)

Geology and Mineralisation

The region of Roper River mine is in the Proterozoic McArthur Basin, which occupies a large majority of the northeast region of Northern Territory. The basin is characterized by a thick succession of Paleo- to Meso- Proterozoic sedimentary sequences. In Meso-Proterozoic, the widely developed Roper Group, consisting sandstones, mudstones, shales and carbonates, was intruded by the Derim Derim dolerite dykes and sills at a geological age of 1324 Ma, and intrusion was mainly in Roper River area.

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Stratigraphy of Roper Group and Intrusion of Derim Derim Dolerite (Bodorkos et al, 2020) 

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Distribution of Derim Derim Dolerite exposure according to Northern Territory Geological Survey (NTGS) 

Laterization of Derim Derim Dolerite


The Derim Derim Dolerite is a continental tholeiitic dolerite that varies from aphanitic basalt to holocrystalline microgabbro in texture and composition. It comprises of plagioclase feldspar (variably altered to sericite), clinopyroxene (pigeonite-variably altered to epidote and chlorite), and iron-titanium oxides (magnetite, titanomagnetite and ilmenite, approx. 3-5%).


Historical sampling and testing indicates that the dolerites have undergone intensive in-situ laterization and contains heavy minerals of magnetite, titanomagnetite and ilmenite. Pisolites were also formed during intensive insitu lateritisation. Angular sandstone fragments and thin horizons of angular sandstone clasts suggest that the laterites were reworked locally into poorly bedded, pisolitic, strongly ferruginous, clay-rich eluvial and colluvial regolith deposits of enriched heavy mineral content where the heavy mineral grains are mostly euhedral and non-braided as a result of limited transport. They overlie weathered dolerite and form the bulk of the immediate resource potential. “Black soils” containing smectite clays (responsible for desiccation cracks during the dry season) in contact with the pisolitic regolith and often overlying weathered dolerite also contain heavy minerals that have been trapped by the cyclic shrinking and swelling habit of the smectite. These heavy mineral grains are more strongly braided. Alluvium in drainage channels comprising unconsolidated sands and grits also contains heavy minerals confined to the coarser layers.

Ilmenite-bearing regolith including Pisolitic Soil and Black Soil form the ore of Roper River Ilmenite Mine. Large-scale drilling program and surface sampling have confirmed that ilmenite-bearing regolith shows a correlation with underlying dolerite distribution, which presents a guide for exploration.



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Regolith Profile

Pisolitic Soil

Black Soil


Ilmenite Accumulation 

Pisolitic Soil

Ilmenite in Pisolitic Soil.jpg

Concentrated Ilmenite 

Ore Deposit Characteristics and Titanium Grade


  • Wide distribution (large quantities)

  • shallow and consistent thickness 2-3 meters (surface mining)

  • 6% heavy mineral (HM) 5% ilmenite (50% TiO2) on average (high grade)

  • Lack of other heavy mineral (HM) (simple separation, low impurities) 

  • High slimes (small grain-size) (excluded from current resource definition and separation)

Vanadium Potential

Vanadium Potential  


  • XRF analysis suggest ilmenite concentrate contains 0.43% V2O5

  • Vanadium-rich magnetite were identified in current defined resources

  • Vanadium-rich magnetite were widely identified in the underlying dolerite

  • further sampling and analysis will be conducted to understand the Vanadium potential

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