Advances in Exploration and Ore Deposit Geochemistry – Como, Western Australia 2013

16 l

Bulk Chemistry, Infra-red Spectroscopy and Geometallurgy of Paladin’s Manyingee Deposit, Carnarvon Basin, Western Australia

ANDY WILDE1, STEVE SUGDEN2 and JIMMY THOM1

Bulk Chemistry, Infra-red Spectroscopy and Geometallurgy of Paladin’s Manyingee Deposit,

Carnarvon Basin, Western AustraliaANDY WILDE, STEVE SUGDEN, JIMMY THOM

1 Paladin Energy Limited Corresponding author:

2 ioGlobal Pty Limited

Onslow in Western Australia (Fig. 1). It was discovered by

Exploration Pty Ltd) in 1974. Total completed 400 mud rotary drillholes and a six month 'eld leach trial which

*e project was acquired by Paladin Energy in 1998. *e

3O8 at 0.09% and Paladin’s geological analysis has identi'ed an exploration target of

3O8.

occurs at 50 to 150 metres below the surface within Lower Cretaceous channel sediments incised into Proterozoic granitoid basement. *e aquifer unit and main ore host is

the 40-70m thick Birdrong Sandstone, which overlies 20m of conglomerate. A 20-40m thick arkose directly overlying basement is interpreted to be a veneer of in-situ weathered granite. *e channel is capped by the

Shale and younger sediments. (Fig. 2)

*is work was designed to help develop a geometallurgical

red spectroscopic data. Geochemical data for the project comprises three data sets. *e 'rst set comprises approximately 1,000 drill samples collected and assayed in the late 1970’s and early 1980’s. Analytical techniques were poorly documented but are believed to have been AAS and/

whole rock analyses is available from the same era. *e third sample set is derived from Paladin’s 2012 drilling program, and consists of 270 samples of quartered core, analysed by ICP-AES following four acid digestion. Total, inorganic and organic carbon analyses are also available for this latter dataset. QA/QC data for the older data are lacking but a comparison with the 2012 dataset provides some con'dence in their quality.

data suggested the possibility of several discrete ore types. Cluster analysis was undertaken using the software ioGAS in order to establish whether a rigorous and objective analysis of the chemical data would support the subjective identi'cation of discrete ore types. Four separate cluster analyses were undertaken. *ese revealed logical groupings which could

clusters generally (but not always) had higher uranium values. *ree reduced groupings were seen: uranium with high carbonate and/or sulphur, low uranium with high carbonate

± sulphur and high uranium with high white mica ± carbonate ± sulphide. Oxidised groups showed two signatures: a mineralised group with high Se, Sr, P, ± Sc and a low uranium (barren) group.

Further geochemical analysis using scatter plots and molar calculations con'rms the presence of carbonates such as dolomite, siderite and possibly ankerite (Fig. 4). Dolomite and siderite are associated with

Figure 1. Location.

Figure 2. Typical cross section.

Advances in Exploration and Ore Deposit Geochemistry – Como, Western Australia 2013

17 l

reduced sediments and potential exists to predict leaching performance of the uranium ores using these tools.

Infra-red data di5erentiate oxidised and reduced sandstones with ease and permit a quantitative estimation of redox

intense absorption around 490 nm, which is attributable

as reduced, however, have a prominent absorption at 2210 nm which is due to much higher volume of matrix white

in siderite. Despite the presence of siderite in many of the samples, absorption in the range 2270 – 2380 nm is generally weak to absent.

*is study has shown that a combination of bulk chemical and infra-red spectroscopic data can be used to e5ectively de'ne di5erent ore types and carbonate species at

Bulk Chemistry, Infra-red Spectroscopy and Geometallurgy of Paladin’s Manyingee Deposit,

Carnarvon Basin, Western AustraliaANDY WILDE, STEVE SUGDEN, JIMMY THOM

Figure 3. Cluster analysis geochemical $ngerprint.

Figure 4. FE and C vs . C (Dolomite removed) Molan plots.