Opinion by

The legal questions involved in this case are well settled. The trouble is with the questions of fact. There is no doubt that the owner of coal lands may mine and remove his coal in a proper manner. If the drainage from the mines falls into *497and pollutes a stream of water and injuriously affects lower riparian owners, this fact alone will not impose liability on the owner of the coal. Sanderson v. Coal Co., 113 Pa. 126. He may deposit the culm and refuse from his mines on his own land where they will be safe from encroachment by ordinary floods. If an extraordinary flood should reach and carry away any portions of the culm so deposited, and leave it on the lands of lower riparian owners, he is not liable for the injury so sustained. But he must deposit the culm and refuse on his own lands. He has no right to throw it into the streams, or leave it where ordinary floods will carry it down upon the lands of others; Lentz v. Carnegie Bros., 145 Pa. 612. If he does throw it into the stream, or leave it where ordinary floods will carry it away, then the injury that his neighbor may suffer therefrom is not the natural and necessary consequence of the rightful mining of coal, but of the want of proper care in disposing of the refuse product of the mines. For an injury resulting from the want of care, an action will lie. It may be convenient or economical for the coal owner to throw the refuse of his mines into the streams, but that is not enough. He is bound to consider the rights of others. If he takes the risk of injuring others to save trouble or expense for himself, he makes himself liable for the loss his conduct may inflict on his neighbors. These general rules are settled by a multitude of cases.

The controversy in this case was mainly over the facts. The plaintiff alleged that the defendant company used the stream called Bear creek to carry away large quantities of its refuse, and that this was brought by the water down upon his lands, thereby injuring them and greatly impairing their value. The defendant denied such use of the stream, asserted that so much of the refuse as was thrown into it was thus disposed of in order to make room for a retaining wall to protect the culm pile from ordinary floods, and that the deposit of refuse on the plaintiff’s land was the work of an extraordinary flood for which the defendant could not be held responsible. These were questions for the jury, and the evidence relating to them was of such a character that we do not see how it could have been withdrawn from the jury. The verdict must be taken as establishing the facts that the defendant did put large quantities of refuse into the stream and that it descended upon the lands of the plaiu*498tiff and lodged there. ■ Upon these facts the plaintiff was entitled to recover his actual loss.

The motive with which an unlawful act is performed is ordinarily immaterial, except as it may bear upon the question of the plaintiff’s right to exemplary damages. The learned judge of the court below did not, as we understand him, submit the question of the plaintiff’s right to exemplary damages to the jury, but instructed them that the measure of the plaintiff’s loss, and consequently of his damages, was the difference in the rental value of his land caused by the descent of the refuse upon it. This was the correct measure of the actual damage suffered from the defendant’s act, regardless of the motive which inspired it, unless the culm could be removed and the land restored to its original condition for a less sum, and this was not alleged.

It was also contended upon the trial that if it be conceded that refuse was thrown into the stream and carried by it part of the way to the plaintiff’s land, yet, as the evidence shows that it was washed upon the land, or made its actual descent from its last resting place under the influence of an extraordinary flood, the plaintiff’s loss is chargeable to an extraordinary flood and not the defendant’s act. It is undoubtedly true that no liability arises from the loss occasioned by an extraordinary flood. Such flood is treated as the act of God, for which no action lies. If therefore the evidence in this case had shown the exercise of proper care on the part of the defendant to protect the culm from the action of the water, and that an extraordinary flood overcoming the precautions employed had swept it away, the rule invoked would be applicable. If on the other hand, the evidence satisfied the jury that the defendant had thrown the culm into the stream where every flood, as well as the ordinary current, would. act upon it, and carry it gradually down the stream, the fact that an extraordinary flood quickened its descent and gave the final impulse that lodged it on the plaintiff’s land is not enough to bring the case within the rule. Upon the latter state of facts, the extraordinary flood is not an unlooked-for and overpowering force invading the defendant’s grounds and sweeping away that which an ordinary flood would not reach, but a force co-operating with the negligence of the , defendant. It would, upon such a state of facts, add its energy *499to the defendant’s neglect, and so expedite the natural process of descent which began with the defendant’s unlawful act of throwing the refuse into the stream.

Several assignments of error are to the rejection of evidence offered to disprove negligence. This was a competent line of evidence if the offers were of matter that was competent. Whether a given act is performed in a prudent and proper manner is a subject upon which a witness qualified to speak may express an opinion. He may state the manner of the performance and whether the precautions taken or the work done were reasonably sufficient for the purpose in view. But whether a line of conduct, like the defendant’s management of its culm pile, is negligent or careful is for the jury after the facts are laid before them. We think also that so far as the offers related to particular facts the court below was right in holding the facts irrelevant. Thus Womelsdorf was called as an engineer, and an offer was made to show by him as an expert witness that “ In putting up these walls and doing the work that we did, we did what we should have done; I mean to say that we did it in a skillful and workmanlike manner, well calculated to produce the desired effect.” The objection to the relevancy of this offer rested on the fact that no complaint was made about the manner in which the walls were constructed. The walls were not in the controversy. The complaint was that culm and refuse had been thrown in the stream by the defendant in large quantities and the character of the walls threw no light upon that subject. The same objection exists to the offer to show that “ The unprecedented flood of 1886 did great damage to the defendant’s property and caused the mines to be idle for three weeks.” This tended neither to deny nor excuse the acts charged against the defendant and was rightly held to be irrelevant matter. The recovery seems to us to be large, but the learned judge of the court below could not have been of this opinion or he would have set aside or reduced the verdict.

The assignments of error are not sustained and the judgment is affirmed.