![]() ![]() ![]() ![]() Initially each deposit will be mined by conventional open pit mining. Two different but complementary mining methods for the Merlin kimberlite pipes have been planned. The pipes are located within four main clusters over an area of. The sagged nature of the infill sediments, the upturned edges with associated slickensides, the presence of a basal non-kimberlitic conglomerate and the thickened iron pisolite profiles, all suggest that the Cretaceous aged sediments have subsided into the pipe structures possibly due to solution weathering of the kimberlite. The kimberlites are strongly weathered to 60m - 80m depth from surface and appear to have sunk back down into the craters, that have been in-filled with Cretaceous sediments that are up to 40m thick. In the case of Palomides and Sacramore they coalesce into a larger single vent named PalSac. In the softer sediments beneath the Bukalara/ Proterozoic unconformity, some pipes increase in diameter. At surface the shapes of the pipes are circular to elliptical and maintain their regular shape and near vertical sides within the Bukalara sandstone. The Merlin pipes are small, with the diameter of the upper levels varying between 50m–125m. Thin deposits of Cretaceous sediments and laterite overlie the pipes. The Merlin kimberlites are Devonian in age (382 million to 352 million years ago) and intrude mid-Proterozoic shales and dolomites of the McArthur Group and the unconformably overlying Cambrian Bukalara Sandstone. The Merlin kimberlite field is situated on the eastern side of the North Australian Craton, ~100km south-west of the coast of the Gulf of Carpentaria. ![]()
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