This chapter is intended to encourage the improvement of land and water adversely affected by mining and oil and gas extraction, to aid in the protection of wildlife, to decrease soil erosion, to aid in the prevention and abatement of the pollution of rivers and streams, to protect and improve the environmental values of this Commonwealth and to eliminate or abate hazards to health and safety. It is the intent of the General Assembly to encourage voluntary reclamation of lands adversely affected by mining or oil or gas extraction. The purpose of this chapter is to improve water quality and to control and eliminate water pollution resulting from mining or oil or gas extraction or exploration by limiting the liability which could arise as a result of the voluntary reclamation of abandoned lands or the reduction and abatement of water pollution. This chapter is not intended to limit the liability of a person who under existing law is or may become responsible to reclaim the land or address the water pollution or anyone who by contract, order or otherwise is required to or agrees to perform the reclamation or abate the water pollution.