Economic Geology 5350
Subject: Magmatic Chromium Deposits
Ore Mineralogy and Tenor
The only economic mineral of chromium is chromite; a variety of the spinel group that has a chemical formula of (Fe,Mg) (Cr, Al, Fe)2O4. Theoretically the mineral contains 68 % Cr2O3 and 32% FeO but Fe+3 may displace some Cr+3 reducing the Cr2O3 content to as little as 40%. To be commercial, ores usually contain a minimum of 45%Cr2O3. There are three types of ore: chemical, refractory, and metallurgical. Metallurgical contains 45-56 Cr2O3 with a high Cr:Fe ratio (2.5 to 4.3); chemical contains >44% Cr2O3 3 with a Cr:Fe ratio of at least 1.5; whereas refractory contains 30-35%Cr2O3, 25-32% Al2O3 with a Cr:Fe ratio of 2-2.5:1 and very low iron content. Common gangue minerals associated with chromite are olivine, orthopyroxene, serpentine, and calcic-plagioclase. Chromite is closely associated with Mg and Ni in ultramafic rocks; peridotite contains 1000-3000 ppm Cr, where 1% is not uncommon. Gabbro however averages 200 ppm Cr.
JD, Is our Cr commercially viable?
Thanks always..
Bernard
See JD answer, he is optimist that SPQ has hit good result as it is just the prelim and in the early stage of exploration...sure he is the mentor for me...
Bernard