The Orelia gold deposit is located 10 kilometres south west of the Bronzewing processing plant and approximately 450 kilometres north of Kalgoorlie. The Project is accessed via Leinster, located 45 kilometres to the west. Orelia is located on granted mining licence M36/146 and is 100% owned by Echo.
The Orelia gold deposit (incorporating the Orelia, Calista and Cumberland shear zones) has been previously mined during a number of campaigns since 1988. Approximately 400,000 ounces have been produced from the existing open pit to a vertical depth of approximately 100 metres below natural surface. It was last mined in April 2013 and treated through the Bronzewing processing plant which is now 100% owned by Echo.
Geology and geological interpretation
The main host rocks of mineralisation at Orelia are deformed and altered tholeiitic basalts, concordant dolerite units and felsic to intermediate sedimentary rocks. Cross-cutting felsic to
intermediate porphyry dykes intrude the stratigraphy along pre-existing structures. Gold mineralisation typically occurs as southerly plunging ore-shoots at the intersection between steeplydipping transgressive faults and favourable lithological units, along fold hinges and on lithological contacts.
At Orelia gold values are not necessarily associated with total sulphide content. In sedimentary lithologies much of the sulphide is considered primary and is unrelated to the gold. The gold is associated with the hydrothermal phase of sulphide formation that consists of pyritepyrrhotite±chalcopyrite. Gold related alteration consists of biotite-sericite-carbonate altered deformation zones.
The deposit comprises a number of shallow trending high grade gold shoots with dimensions of approximately 50 metres in vertical extent and 25 metres in width and extending over 500 metres down plunge. Confidence in the geological interpretation is good with the latest infill drilling allowing a detailed interpretation of the controls on mineralisation. 6 Geological logging and interpretation allows extrapolation of drill intersections between adjacent sections and boundaries are determined by the spatial locations of the various mineralised structures. Mineralisation is confined to individual wireframes with oxide, transition and fresh material individually assessed with oxidation profiles established and assigned into the block model.