A few weeks ago I had mentioned in one of my comments that

"Almost every object that is used in modern societies contains some
material that has been extracted from the earth.  A huge amount of
energy is used in crushing rocks to a fine enough size that surface
chemistry may then be used to extract a particular metal.  Assuming
that we would like to use energy more efficiently, is there a way our
knowledge of mechanics can be used to minimize the energy used in
crushing rocks?  A huge number of people have worked on this problem -
yet an optimal solution seems as far away as ever. "

A meeting with my ex-classmate Dr. Barun Gorain of Barrick Gold Company  last weekend showed me that there are still quite a few problems of that nature in the mining industry.  In fact, Barrick is willing to spend as much as $10 million to solve one such problem.  The main site is called Unlock the Value and the bit that they are willing to offer cash for is a particular silver recovery operation.  Barun tells me that proposals are already in and are being evaluated - but I'm not sure whether those are for the silver problem or some other issue.   Can mechanicians help solve the problem?  Some of you might want to give it a try.

-- Biswajit