Mt Todd lies towards the south end of the Pine Creek Geosyncline,
sandwiched between the Cullen Batholith and the Edith Falls Basin, in an
area of regionally metamorphosed sandstones, siltstones and shales. The Batman deposit, some 3 km west of Mt Todd is a sheeted quartz
vein system hosted within greywackes of the Palaeoproterozoic Burrell
Creek Formation (Finniss River Group). The gold-bearing quartz veins,
trending 010-020 and dipping 60-70E, are commonly 0.5 to 5 cm
wide and occur at intervals which are from 10 cm to 1 m apart. Gold
tends to be restricted to the quartz veinlets and immediately adjacent
country rock. Grade Control utilises two 4 m 'collar' samples which are
collected from each 8 m production blasthole. The irregular distribution of the quartz veins and erratic gold
mineralisation has resulted in a disseminated 'salt and pepper' type of
gold occurrence, with only a poorly defined footwall. Delineation of ore and waste blocks for mining uses an approach which
combines the smoothing effect of kriging with a pragmatic view of the
raw data. Large ore blocks with simple geometry help to minimise mining
dilution, reduce block variance and give good reconciliations to
interpreted ore tonnes and grade. Daily mine face advance is reported against truck counts and provides
continual comparison with budgeted production. All data processing uses
Gemcom software, together with Lotus spreadsheets.