Sinopec , a shale oil producer during those times , shut down its oil shale operations in the beginning of the 1990s .
From 1965 oil shale usage in Fushun started to decline with the discovery of Da Qing oil field in the 1960s .
Sinopec , a shale oil producer during those times , shut down Fushun 's oil shale operations in the beginning of the 1990s .
From 1965 oil shale usage in Fushun started to decline with the discovery of Da Qing oil field in the 1960s .