rashel Posted June 2, 2008 Share Posted June 2, 2008 Leaching, the recovery of copper from the drainage water of mines, as a method of the extraction of minerals, it was well established as early as the eighteenth century, but until about 25 years ago miners did not realize that bacteria take an active part in the process. A. as a method of the extraction of minerals, it was well established B. as a method of the extraction of minerals well established C. was a well-established method of mineral extraction D. was a well-established method of extracting mineral that was E. had been a method of mineral extraction, well established Quote Link to comment Share on other sites More sharing options...
rashel Posted June 2, 2008 Author Share Posted June 2, 2008 sorry wrong thread...in hurry i posted it Quote Link to comment Share on other sites More sharing options...
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