Opinion by
Beaver, J.,It may be seriously doubted whether the testimony of the plaintiffs, the appellants here, in any sense overcame the defendants’ answer which was entirely responsive to the bill and set forth, with great particularity the facts, as they claimed them. “ The answer of defendant, when responsive to the bill, is conclusive, unless contradicted by two witnesses or by one witness and such corroborating facts and circumstances as are equal to the testimony of another witness: ” 6 P. & L. Dig. of Dec. 8892.
*175The conclusions of law, of which the appellants complain, as embraced in the thirteenth, fourteenth, fifteenth, sixteenth, seventeenth, eighteenth, nineteenth and twentieth assignments of error, necessarily followed from the findings of fact which are complained of in the first twelve assignments. After a careful reading of the testimony more than once, we are unable to convict the trial judge in the court below of error in any of his findings of fact. Hopkins, the plaintiff, with whom the agreement with David Steen & Sons, under whom the defendants claim, was made, is the sole witness as to the terms of the original grant under which the entry or drainage drift now sought to be closed, or rather prevented from being opened, was driven. His memory, as he distinctly admits, is unreliable. He says : “ It is a good many years ago and I want to be just right, if I could, but I have forgotten some of it I think in the meantime.” His testimony relates rather to the conclusions at which he arrived and which he maintains than to the conversation which constituted the agreement.
He was contradicted as to material parts of his testimony (a) by William J. Steen, who was one of the parties with whom the agreement was made and who was present at a conversation covering the agreement and what was contained in it, after the first conversation between the plaintiff, Hopkins, and David Steen; (i>) by one of his cotenants, to whom he communicated the terms of the agreement with David Steen & Sons, soon after it was made; (c) by the action of Steen & Sons who, immediately after the agreement, expended some $6,000 in digging and supporting the entry through the appellants’ land, which expenditure is inconsistent with the plaintiffs’ contention.
1. Under the facts, as found by the trial judge in the court below, all of which are based upon and clearly justified by the testimony, the drainage drift was located by the original parties to the license at a point where the drift, when driven, would drain some forty acres of coal belonging to the plaintiffs but since sold to third parties. The plaintiffs, therefore, received a valuable consideration for the grant of the license.
2. The parties to whom the license was granted unquestionably expended a large amount of money upon the faith of it. There is no contradiction of the testimony that 16,000 was *176expended in driving and properly supporting this entry or drift.
3. The coal upon the original tract owned by the parties to whom the license was granted has not been exhausted. Not only are the pillars and supports not yet withdrawn, but there is a corner of the coal, estimated to contain about three acres, still remaining.
The license granted by the plaintiffs, the owners of the land, to David Steen & Sons was, therefore, under our cases in Pennsylvania, clearly irrevocable, at least so far as the coal owned by David Steen & Sons and since conveyed to the defendants was concerned.
Licenses are of two kinds, simple or revocable, and, coupled with a grant, irrevocable. Simple licenses are revocable at the will of the grantor. A license is irrevocable when it is coupled with a grant or when the licensee has, on tiie faith of the license, spent money in executing works of a permanent character on the land. In some states even parol licenses, without consideration, are held irrevocable when executed on the ground of equitable estoppel: 2 Bouvier’s Law Dic. 222. Pennsylvania is one of the states which holds a license irrevocable when executed, particularly when money has been expended upon the faith of it: Lacy v. Arnett, 33 Pa. 169. The general principles governing licenses and their irrevocable character by equitable estoppel are well stated in the syllabus of Baldwin v. Taylor et al., 166 Pa. 507. It is needless to enter into any general discussion upon this subject or to multiply authorities.
It does not seem to us that the plaintiff comes into court with such a case as justifies equitable relief. He who seeks equity must do equity. The permanent closing of the drain, the opening of which is sought to be restrained by the bill in this case, would work gross inequity in all directions. The defendants, who purchased Steen’s rights, with the drift or entry in plain view, would be prevented from draining and ventilating their mines, except by the expenditure of large amounts of money in sinking shafts and using pumps, in which event the water must flow over some one’s land. The purchasers of the coal from the plaintiffs, who own the land, through which the entry was driven, would also be deprived of its use. The accumulations of water in the drift, if the *177mouth of it were closed, must find outlet somewhere by percolating through the soil and, inasmuch as it is apparent that, even before the entry was driven, the water found its way over the lands of the plaintiff, no harm can be done by concentrating it and discharging it through a drain to the creek. Opon all grounds, the court below was clearly justified in holding the license irrevocable, under the conditions now existing and the facts as found, and in dismissing the plaintiffs’ bill.
We have discussed this question principally from the standpoint of the plaintiffs in the bill, who are the owners of the land. If the tenant is at any time specially injured, he has a complete remedy at law.
The decree of the court below is affirmed and the appeal dismissed at the cost of the appellants.