Tinjauan hukum mengenai kewajiban divestasi saham dalam rangka penanaman modal asing di bidang pertambangan mineral menurut undang undang nomor 4 tahun 2009 tentang pertambangan mineral dan batubara studi kasus renegosiasi kontrak karya PT Freeport Indonesia = Legal consideration on share divestment obligation in foreign investment in mineral mining area according to law no 4 of 2009 on mineral and coal mining case study renegotiation of contract of work of PT Freeport Indonesia