A Summary of Major Mineral Resources, Mines and Projects, 2nd Edition |
GUMIGIL'S MARLBOROUGH CHRYSOPRASE
493305
15KM SOUTH OF MARLBOROUGH, 165KM NW OF GLADSTONE.
Latitude -22.9661 Longitude 149.8450
OPERATING
AMG Zone 55 791716 mE 7457405 mN
1:100 000 sheet Number and Name: 8852 MARLBOROUGH
3/January/2006
Other Names for Deposit / Mine |
Marlborough Chrysoprase
Gumigil
CHRYSOPRASE
LARGE
>100 tonnes CHRY
Published Reserves/Resources |
INFERRED MINERAL RESOURCE
BR 5920 Published in 1998
1660 Tonnes CHRYSOPRASE
Resource figures listed above have been extracted from Company Annual reports or published literature.
1998
LOUTHEAN PUBLISHING PTY LTD AND MINMET AUSTRALIA PTY LTD
BR 5920
THE AUSTRALIAN MINES HANDBOOK 1998/99 EDITION.
Major Mining Related Events |
Operating Mine Life: 1978 to 2020 Mining by Gumugil Pty Ltd. Mine life is from 2000.
OPEN CUT MINING
The mining method is mainly to rip the laterite with a bulldozer. A |
person walks behind the bulldozer marks exposures of chrysoprase |
and these are picked up by hand or dug out with a backhoe. |
ML
5791
GUMIGIL PTY LTD
100.00%
Host Rock/Cover Sequences |
MARLBOROUGH BLOCK
Princhester Serpentinite / NEOPROTEROZOIC to EARLY PALAEOZOIC
GENERAL ORE BODY MODEL
RESIDUAL DEPOSIT
DETAILED ORE BODY MODEL
LATERITIC NICKEL
ORE
CAINOZOIC
Nickel-cobalt and chrysoprase mineralisation occurs within shears at the edges of the ultramafic thrust blocks. Chrysoprase occurs largely |
in a saprolitic zone ranging up to 70m in thickness, overlain by a ferruginous silicified cap, 14m to 30m thick. |
In a transition zone between the saprolite and the underlying serpentinite, magnesia-rich material contains nodules of chrysoprase, some |
of which are very good quality. |
Flatly and steeply dipping veins of chrysoprase, colourless to white quartz, chalcedony and common opal form a box-like network in the |
saprolitic zone. |
Veins of gem quality chrysoprase range up to 8 cm in width but form a small proportion of the total quantity of vein material. Manganese |
oxides and magnesite are commonly associated with veins of good quality chrysoprase. |
The friable nature of the wall rock allows the chrysoprase to be broken out free of the waste rock.