Overview

Mine Type	Open Pit
Status	Closing / Closed
Commodities	Ilmenite Apatite
Mining Method	Truck & Shovel / Loader
Production Start	...
Mine Life	...
Snapshot	The Goondicum ilmenite and apatite mine ceased production in September 2019. Status: Remediation ongoing Work is expected to be completed by October 2022.

Deposit type

• Hybrid

Summary:

The deposit type is rare in this part of Queensland. It is a flat lying residual oxide deposit of a weathered gabbro intrusion that has had modifications from surface water flow and soil creep. The host rock comprises a combination of weathered material and alluvium. Ilmenite mineralisation occurs as liberated fine grains often concentrated by surface water into more slimes-rich material but the concentration may in part be related to an underlying primary concentration in the gabbro. The gabbro appears to have a primary mineralogical zonation associated with the arcuate margin of the intrusion. The ilmenite has been widely distributed throughout the mining lease with no obvious specific lateral concentrations.

The mineralisation is associated with the Goondicum Gabbro which Groen (1993) had mapped from the crater rim to the centre as comprising a ‘poikilitic marginal zone’ (hornblende gabbro), ‘lower zone laminated gabbro’, and ‘macrorhythmic zone’.

The relatively complex weathering history of the gabbro has produced two main host types for ilmenite mineralisation. The 'clay/sand' unit or ‘CS’ is believed to be an eluvial/colluvial deposit i.e. some in-situ material and some transported material possibly due to both gravity slip and alluvial processes. The second type is 'decomposed gabbro' or ‘DG’, implying a less weathered eluvial or in-situ deposit. A subset of the clay/sand unit is the 'colluvium' unit or ‘CL’, and this may have had a more water transported-related origin. The CS occurs at or near surface and includes the uppermost 20-30cm of the soil profile, designated in the drillhole logging as 'soil horizon' or ‘SL’. The CS can range in thickness, up to several metres, especially where the CL unit is associated. The CL is an important sub-set of the clay/sand mineralisation, having high slimes content, and may have formed from localised damming of alluvial channels resulting in localised flooding where the clay material in suspension settled out in depressions.

Ilmenite deposits also occur along modern stream channels as terrace remnants, which the reactivated stream has partly eroded. Less frequently, palaeo-stream channels are encountered which are filled with gravity flow colluvium with variable ilmenite grades.

The mineralisation is essentially flat lying with an undulating base. For the ML its dimensions are 3,000 x 1,500 metres with an approximate viable range in thickness of 2–10metres (low grade mineralised DG can add to a maximum thickness of 25metres). For the MLA the mineralisation dimensions are 4,000 x 2,000metres with an approximate viable range in thickness of 2–10metres (low grade mineralised DG can lead to a maximum thickness of 25metres).

The fundamental geological control to the mineralisation is the underlying spatial distribution of the gabbro and its ilmenite content, followed by the topography at the time of the different weathering/erosion phases. Ilmenite grades are not entirely related to specific weathered rock types although there is a marked segregation between the high slimes units, CL and CS_H, having higher grades than the low slimes CS_L and DG host units. The ilmenite grades of the DG unit are more directly related to the original grade within the gabbro.

Mining Methods

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Comminution

Crushers and Mills

Processing

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Production