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Gold/Mining/Energy : JABA INC.(c.jba) -- Ignore unavailable to you. Want to Upgrade?

To: Larry Macklin who wrote (583)	9/14/1998 11:38:00 PM
From: Chuca Marsh	Read Replies (1) \| Respond to of 1044

Larry, they did not say that, I think they said that THEIR IN GROUND SULFURIC ACID pit proposal which will be in-place leach is at 30 to 50 cents and hence NOT as costly as the lead companies at 90 cents mentioned in Montana and further still less than the periphery copper projects mentioned as 30-70 cents,,,so that 70 cents is the high FOR STANDARD CN ( Cyanide) Open Pit Leach Projects ( which jaba will not have for this project)...so RE:<<.. es at Butte, Montana or Bisbee, Arizona. Costs are normally considered high - up to 75 to 90 cents per pound of copper produced. Many of the 'porphyry copper deposits' were geologically thrust upwards long ago, became exposed to ancient weathering at and beneath the earth's surface, and had their original chalcopyrite sulfides changed to other sulfide minerals that are soluble in weak sulfuric acid - the same acid that results from natural oxidation of sulfides. These ores have generally been mined from open pits, hauled, placed in dumps (large piles with impermeable "plastic lined" bottoms known as pads), and then sprinkled with a weak acid solution in water that dissolves the contained copper. The solvent solution trickles down through the dumps to an impermeable pad, dissolving copper as it goes, and then the copper-laced fluid travels along the pad to collection ponds from which it is piped to a plant for chemical removal of the dissolved copper. This method is called 'heap leaching' and solvent extraction. After the leaching is finished, the piles of copper-stripped rock are left in place near the original mine site. Although the leaching process is relatively inexpen- sive, overall costs are moderate to high because the ore rock has to be stripped of un-mineralized cover soil and rock, blasted, mined, and transported to the dumps. Costs are generally from 20 to 70 cents per pound of recovered copper. Now - for geologic reasons too complicated to consider here - a few 'porphyry copper deposits', when they were exposed to weathering and erosion, were oxidized to a different type of mineral, the hydrous copper-silica mineral called 'chrysocolla' (pronounced 'kriss-ah-cola') and other green and black copper oxides. This green mineral forms below the ground surface, typically along a web of veinlets and fractures, but also as spots and masses. In oxide form copper can be dissolved in either a weak acid or alkaline solution. If a solvent could be pumped down one set of drill holes (or 'wells'), it would dissolve the copper out of the chrysocolla. The copper-bearing solution could then be directed through cracks in the brittle rock to another set of wells for out-pumping and removal. This is another style of leaching called in situ leaching (ISL), the chemical leaching of copper from rock that remains in place. The copper is then chemically stripped from the pumped recovery solution (solvent extraction or SX) and electrically 'plated out' to form pure copper cathodes - electro winning or EW (generally 99.999% copper called electrolytic or wire grade copper), thus the 'solvent extraction-electro-winning (SX-EW)' part of the process name. The cost-saving (and profit!) implications of ISL-- SX-EW are huge, because:..>> Chuca