of mining bituminous coal . . .”; and that the lease was to expire November 1, 1944, but that “If . . . [lessees] shall have complied with and performed all of the terms and conditions of this lease . . . [lessees] shall have the right to renew this lease annually for further periods of one (1), two (2) or three (3) years from, the date of expiration thereof, upon the same terms and conditions as are herein contained” (Italics added.) Defendants went into possession of the property-under this lease and commenced mining operations.
Plaintiff filed this suit on December 10,1947, alleging that defendants’ occupancy of the property was unlawful in that their right to possession expired November 1, 1947 — three years after the original expiration date. It was also averred that even if the lease permitted renewal after November 1, 1947, defendants had lost such right because of their failure to do any mining on the leased premises from April, 1945, to June, 1947, in violation of the provision requiring diligent mining. Defendants, in their answer, denied that the lease limited their renewal right to an aggregate of three years, and further averred that they had mined diligently according to approved methods. Their amended answer, under new matter, averred that the coal was unmarketable and that during the period from April, 1945, to June, 1947, they had procured a cleaning plant on an adjacent property and improved it at a cost of $22,000, in order to make the coal saleable; that plaintiff, through its agents, knew of those activities and approved them; that defendants have always paid the minimum royalties provided by the lease and that they have, in fact, paid to plaintiff royalties of $29,038.30 over the period of three and a half years they have been in possession of the property. Plaintiff’s reply denied or treated as irrelevant all the averments set forth in the answer under new matter. Plaintiff then moved for judgment on