mining and processing of bentonites

    The Taysan Project is located on the south western segment of the island of Luzon in the well developed industrial province of Batangas, 100km south of Manila. The Project comprises of 11254 hectares with two known deposits: a large copper-gold porphyry deposit (the "Taysan Deposit") similar to other copper-gold porphyry deposits previously mined in the Philippines, and the Antipolo Epithermal Gold Mine. The Taysan Project has had a lengthy history under various joint ventures and option agreements since modern exploration commenced in 1968. The majority of work has focused on resource definition drilling and assessment of the Taysan Deposit. Snowden (1995) reported a resource of 391Mt @ 0.30% Cu and 0.21gpt Au (0.2%Cu cut off). Recent Whittle modeling at $2.50/lb copper and $1000/oz gold shows an economic deposit containing 734 Mt at 0.24% Cu and 0.11 g/t Au. A total of 195 drillholes are recorded for about 44,531m, of which 144 holes totaling 36,562m were drilled at or nearby the Taysan Deposit. Feasibility studies have been carried out by BHP Engineering and Pincock Allen & Holt. The project has a 25-year mine life with excellent exploration potential and a 3-year payback. Years 1-7 have very low production costs and a very low strip ratio, 0.56/1, versus an industry average of 2.5/1. The Project includes high grade copper concentrate with gold, silver, magnetite and other by-products. Beneficiation of the bentonite occurs through oxidation of structural ferrous iron. For rapid beneficiation, bentonite clay need to be grinded first by bentonite powder mill, and then is subjected to moist air while the clay is being agitated, preferably by tumbling within a rotating drum, to provide rapid exchange of moisture and oxygen in the air with the bentonite clay aggregates to thereby increase the speed of oxidation of ferrous iron in the bentonite clay. Drying of the thus treated bentonite clay may be then achieved by agitating the clay, again preferably by tumbling within a rotating drum, in the presence of dry air. Bentonite powder manufacturing processes The mining and processing of bentonites is very simple. The mines are open pit and the bentonite is crushed, dried, pulverized or screened for granular products, classified, and bagged and loaded. For organoclays, acid-activated clays, and nanoclays, a wet process is used. This includes blunging at low solids, screening or centrifuging to remove coarse particles, acid leaching or reaction with organic compounds, filtering, and drying. For nanoclays an intense grinding or shearing is required to delaminate the montmorillonite into very thin flakes before reaction with an organic compound.