IRON MONARCH, historically the most important orebody and most northerly of the 4 major deposits on the Middleback Range. It is a deposit of massive hematite developed in an open syncline, plunging NNE at ~30, and hosted by the lowermost portion of the Lower Middleback Iron Formation (LMIF). The most important ore control appears to be stratigraphic. The deposit is fault bound to the east and west, with the east wall zone interpreted as the result of sisistral transpression, and the west wall shear zone as dextral transpression. There are at least 2 generations of dolerite dykes. The NE ore-BIF boundary is marked by the intrusive "North Wall Dyke," a dolerite dyke intruding a shear. The western shear marks a boundary between ore/BIF and deeply weathered quartz-sericite gneiss, possibly mylonitised granite, possibly Archean Cooyerdoo Granite. The southern pit wall is ferruginous schist, thin bands of BIF, and discontinuous dolomite lenses, possibly that stratigraphic transition zone of mixed chert-dolomite-BIF-metasediment between the LMIF, and the underlying Katunga Dolomite. Ore mineralogy is dominantly hematite, trace goethite. The ore has a distinctive blue-grey, massive to brecciated texture, showing occasional relict BIF laminations. The ore supplied both lump and fines products, being a +6-36mm lump product grading 64.5% Fe, with low levels of aluminium and phosphorus, and -6mm fines. The main phase of mining to 1999 produced ~130 Mt. Thereafter mining has been on a campaign basis, mainly from remaining stockpiles of both high and low-grade ore, with production to end of 2009 of ~1,700,000 tonne. From 2015-2018 production estimates are approximate only for the Iron Knob Mining area that includes ore from stockpiles, the main pit, and the Iron Princess. Estimates are for ~8.5Mtonne mined. Remaining resources June 2013 were 19.9Mt @ 60.5%Fe (30/6/2012) plus 5Mtonne at 47%fe from low grade historic stockpiles. Current owners are Simec Mining, part of the GFC Alliance group of companies.