Annual Report GR427 Florina Project for the period 30 July 2016 to 29 July 2017

Abstract

The Florina Potassium-Phosphate Project is based on the Ordovician Florina Formation in the Daly River Basin, which contains glauconite-rich sandstones. Glauconite is a potential source of potassium fertiliser with phosphate credits, suitable for local and national agricultural use. The project is centred on Florina Pastoral Station 70 km west of Katherine. Florina Formation consists of two glauconitic sandstones sandwiched between dolostones. Two fully cored PQ holes have been drilled into the lower sandstone at localities 5 km apart, to better define the vertical and lateral distribution of glauconite. This identifies a 19-meter thick glauconite rich unit (GRU) at the top of the lower sandstone, for which logs and photographs are available. Toll Transport lost the cores whilst in transport to a Perth metallurgical laboratory, so no mineralogical, geochemical or geotechnical information is available. The GRU is 19m thick, and is estimated to contain 35% glauconite mineral. Detailed mapping shows the GRU extends as a flat lying unit over an envelope of 102 km under shallow regolith in the Yujallowan Creek area on EL 30603. This GRU presents an exploration target of some 530Mt. A clean concentrate can be achieved with grind size 106 - 280 micrometre with magnetic field setting of 9400 Gauss. SEM EDS analysis showed that most glauconite grains in the GRU contain abundant inclusions of apatite (phosphorite) at the micron scale. Initial estimate of the chemical composition of the glauconite concentrate is in the range of 7.5 - 9.5% K2O and 2.65% P2O5. Glauconite can be activated in a proprietary flash reactor such that potassium and phosphorus can be leached by cold dilute acids. This presents potential innovative routes to potash production with phosphate credits, that do not rely on complex and expensive process routes. A 183kg bulk sample has been ground and concentrated by WHIMS to produce about 45kg of circa 75% pure glauconite. This has been activated under two temperature and residencetime regimes. Customised CA (citric acid) analyses show significant dissolution of potassium after 28 days. Follow-up kinetic leach tests were conducted on one of the activation states, over an extended period of 18 weeks. This involved cold dilute (5%) citric acid with intermittent shaking. It showed 46% potassium dissolution after 128 days, with the kinetic leach profile still rising as a straight line. Phosphorus dissolution was total and immediate. This suggests full release of potassium may be achieved over an annual plant growing cycle. Further extended-term kinetic-leach CA tests out to 240 days are currently underway. Leach results continue to demonstrate Florina glauconite may deliver either a slow-release potassium fertiliser with phosphate credits, or feedstock for industrial potash with phosphate and sulphates as by-product. Selective leach and precipitation tests involving cold dilute acids, leading to the production of SOP (potassium sulphate) are planned. An in-house semiquantitative Concept Study has been produced which indicates that potash can be produced at low capital costs. Drilling is now required to define a resource, and provide material for further metallurgical and chemical tests.