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.