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Deposit Synonyms
CORONATION WELL; ML 3375; ML 3376; ML 3377; ML 3378; RL 96
Mineral District
LEIGH CREEK-WILLOURAN MAGNESITE
Deposit Summary
4 main magnesite beds along fold axis of a syncline, with bed 4 ave 8m thick. Drilling identified 25 beds averaging 2.2m thick, dip 15-45. Total resource ~215Mt @ ~40%MgO.
Deposit Description
WITCHELINA, magnesite deposit located 60 km NNW of Leigh Creek and 25 km east of Farina occupied a shallow dipping syncline. The syncline was affected by large-scale compressional Delamerian tectonics, resulting in minor parasitic folds and occasional small-scale reverse faulting, with displacements up to 5 m on the limbs of the syncline. The southern end of the Witchelina Syncline plunged shallowly to the north at less than 5 degrees. The shallow plunge resulted in four principal magnesite beds along the fold axis of the syncline. Magnesite Bed 4, with an average thickness of 8 m, was less than 10 m below the surface. Due to the shallow plunge of, and sub-horizontal structure of the beds along the fold axes of the syncline, the waste-to-ore stripping ratio was considered to be low.
The syncline was elongated in a NNW direction. A total of 46 fully cored diamond holes were drilled for 2,157.5 m from 1998-99. Drillhole intercepts showed that 25 beds averaging 2.2 m thick, dipping 15-45 made up the mineable package of magnesite, which occurred within a 500 m wide dolomite/magnesite sequence. A measured ore resource was 23.7 million tonnes (Mt) @ 41.0% MgO. Indicated and inferred magnesite resources were 93 Mt, and 98 Mt respectively, @ 40% MgO. Minor production from both western (MLs 3375-78), and eastern (MLs 4153-55) deposits from 1964-1974 of 5233 tonne, with 2455 tonne production from Witchelina West.
Discovery Year
? 1964
Commodities
Magnesite, Magnesium Oxide
Ore Minerals
Magnesite
Gangue Minerals
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