Overview
Stage | Production |
Mine Type | Open Pit |
Commodities |
- Heavy Minerals
- Leucoxene
- Zircon
|
Mining Method |
|
Processing |
- Electrostatic separation
- Spiral concentrator / separator
- Dewatering
- Magnetic separation
|
Mine Life | 8 years (as of Jan 1, 2019) |
Latest News | Doral’s purchase of MZI’s Keysbrook mine saves jobs July 2, 2019 |
Source:
p. 3
The Keysbrook Mine and operating entity, Keysbrook Leucoxene Pty Ltd (KLPL), were acquired from MZI Resources Ltd (formerly the parent company of KLPL) by Doral Mineral Sands Pty Ltd on 1 July 2019.
Doral Pty Ltd is wholly owned by Iwatani Corporation of Japan. The Doral Pty Ltd includes Doral Mineral Sands Pty Ltd.
Summary:
The project lies within the Swan Coastal Plain, approximately 3 km west of the Darling Scarp (which is the surface expression of the Darling Fault). The Darling Fault separates the Precambrian Yilgarn Block sequences from the Phanerozoic strata of the Swan Coastal Plain. The fault has an estimated maximum displacement of 15 km and, as a result of erosion, lies approximately 1 to 2 km west of the present scarp.
The Swan Coastal Plain extends from the Darling Scarp to the Indian Ocean, and ranges up to 75 m above sea level. A narrow piedmont zone occurs at the base of the scarp comprising alluvial fans and remnants of two strand-line deposits: the Ridge Hill Sandstone and the Yoganup Formation. West of the piedmont zone lies an alluvial swathe up to 10 km wide, termed the Pinjarra Plain. The Pinjarra Plain, comprising the Guildford Formation, ranges in elevation from 6 to 50 m and is overlain to the west by a series of coastal sand dunes. The oldest of these sequences is the Pleistocene Bassendean Sand, which hosts the Keysbrook Mineral Sand Deposit.
The Guildford Formation is characterised by clay, loam, sand and gravel of alluvial origin, with variable laterisation and podsolization. The Bassendean Sand and Guildford Formation have a combined thickness of 10 to 15 m and unconformably overlie about 50 to 130 m of Creataceous Leederville Formation. In the western portion of the project area the Leederville Formation conformably overlies the Cretaceous South Perth Shale, and in the eastern part it conformably overlies the Jurassic Cattamarra Coal Measures.
Summary:
The Keysbrook project covers a shallow orebody with an average depth of two metres, making it very simple to mine and rehabilitate.
Mining involves earthmoving similar to subdivision earthworks, using a small fleet of conventional excavators, front-end loaders, articulated dump trucks, dozers and graders.
First, top soil is removed and stored for rehabilitation. An excavator then removes the ore and stockpiles it next to the Mine Field Unit (MFU) for processing.
At the MFU, ore is mixed with water and passed over vibrating screens to remove coarse non-mineralised waste. The remaining mineralised ore is then pumped to the Wet Concentrator Plant (WCP) as a slurry.
Mining operations are daytime hours only, between the hours of 7am and 6pm. Ore processing remains a 24/7 operation, with the Mining Feed Unit (MFU) fed by ore from a stockpile during the night period.
Mining has changed from a combined effort of KLPL and contractor personnel and equipment to now solely contract mining using Pinjarra based earth moving company, Raywell Contracting. As a consequence of this change, many of the people employed by KLPL have been re-employed by Raywell Contracting.
Processing
- Electrostatic separation
- Spiral concentrator / separator
- Dewatering
- Magnetic separation
Flow Sheet:
Summary:
The ore is processed in two stages:
1. At the Wet Concentrator Plant (WCP), the ore passes through multiple spirals using water and gravity to further separate heavier minerals from non-mineralised sand. This is a chemical-free process that creates a Heavy Mineral Concentrate (HMC).
The WCP featured overland pumping, thickening and tailings storage infrastructure and had a design throughput of 4.5mtpa to produce circa 119ktpa of HMC. The HMC was processed further at the Doral (Picton) Mineral Separation Plant (MSP) to produce approximately 68ktpa of leucoxene and 28ktpa of zircon concentrate for export.
In December 2017, MZI Resources Ltd commenced modification works on its Keysbrook processing facilities and Picton Mineral Separation Plant (“MSP”). These works were undertaken to increase MZI’s mineral throughput capacity from approximately 4Mtpa to 5.25Mtpa in order to reduce unit costs and improve operating margins across the business. The annual HMC ........

Recoveries & Grades:
Commodity | Parameter | 2018 | 2017 | 2016 |
Heavy Minerals
|
Head Grade, %
| 2.89 | 2.68 | 2.61 |
Reserves at June 30, 2018:
Category | Tonnage | Commodity | Grade | Contained Metal |
Proven
|
53 Mt
|
Heavy Minerals
|
2.2 %
|
1.2 Mt
|
Proven
|
1.2 Mt
|
Zircon
|
11.8 %
|
|
Probable
|
4.6 Mt
|
Heavy Minerals
|
2.1 %
|
0.1 Mt
|
Probable
|
0.1 Mt
|
Zircon
|
10.7 %
|
|
Proven & Probable
|
57.6 Mt
|
Heavy Minerals
|
2.2 %
|
1.3 Mt
|
Proven & Probable
|
1.3 Mt
|
Zircon
|
11.7 %
|
|
Total Resource
|
78.2 Mt
|
Heavy Minerals
|
2.2 %
|
1,710 kt
|
Total Resource
|
1,710 kt
|
Zircon
|
11.8 %
|
|
Financials:
| Units | 2018 | 2017 | 2016 |
Capital expenditures
|
M AUD
| ......  | ......  | ......  |
Revenue
|
M AUD
| ......  | ......  | ......  |
Pre-tax Income
|
M AUD
| ......  | ......  | ......  |
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