ABNR/CastleAsia provided update on the new mining law here. The Jakarta Post published some report on divestment obligations for foreign mining firms here and here. A rather academic discussion is available on a paper here. IFLR published a memo on mining -- quite thorough here. There's a presentation giving a quite extensive overview on mining law here. There is also a short memo from Makarim, as well as Roosdiono.

Well, that should save some time for your research work -- and to ask more difficult question to your lawyers :)