Analisis kedudukan PKP2B berdasarkan perubahan ketentuan mengenai kontrak pertambangan menurut UU No. 11 tahun 1967 tentang ketentuan-ketentuan pokok pertambangan dan UU No. 4 tahun 2009 tentang pertambangan mineral dan batubara = Analysis coal mining agreement position based on amandement of provisions on mining contracts according to law number 11 of 1967 regarding principal provisions of mining and law number 4 of 2009 regarding mineral and coal mining