(5 ILCS 615/19) (from Ch. 96 1/2, par. 5019)
    Sec. 19. After the issuance of any petroleum lease the lessee shall proceed to develop the petroleum in the lands covered thereby through the drilling of such wells as will efficiently extract the petroleum therefrom and such development shall take into account the productiveness of the producing horizon, the depth at which it occurs, the average cost of wells, the market requirements obtaining at any given time, and the maintenance of proper oil and gas ratios. The Department shall determine, either by rule or regulation, or by inclusion in the terms of any lease, the rapidity and extent of development of the oil, gas or other petroleum field embraced by such lease.
(Source: Laws 1951, p. 1167.)