GEOLOGY AND FORMATION OF NEVRUZTEPE Fe-Cu SKARN MINERALIZATION (YEŞİLHİSAR-KAYSERİ)

The Nevrurtepe iron-copper prospect is a skarn near Yesilhisar (Kayseri). It has been overlooked as a potential producer of copper. The skarn was generated in Permian to Jurassic carbonate rocks by the Eocene Yahyali granitic pluton. Lithologic units, including skarns, dip about 15 degrees southward. Skarns are both prograde (garnet and diopside) and retrograde (epidote); both exoskarn and endoskarn exist. Most of the magnetite is in a quartz-sulfide stage in retrograde skarn that is cut by veins and lenses containing quartz-pyrite-chalcopyrite. Granite and mineralized skarn are rare at the surface. From 2013 to 2015, 31 drill holes (totaling 6.178,5 m) encountered skarn to a depth of 450 m. Mineralized zones vary from 1,2 to 54,7 m thick. Fe mean grade ranges from 12% to 49%; mean copper grades vary from 10 to 4650 ppm. The deposit contains 5.096.788 tonnes of mineralized material. Microscopy on samples of drill core shows that the ore minerals are primarily magnetite, hematite, and chalcopyrite. Some magnetite is altered to hematite. Experiments show that with grinding to 100 microns the iron can be beneficiated to 66%. Waste from separation of the magnetite is 0.16 to 0.19% Cu; with flotation this was beneficiated to 19% Cu.