delivered the opinion of the court,
This was an action of trespass for mesne profits. Twenty errors are assigned. It is unnecessary to consider each separately. They involve a few principles only. The controlling questions are, the value of the ore taken; the manner of proving that value; and the character of the improvements which may be recouped or set off against the value of the ore mined and appropriated by and under the defendants.
1. The evidence shows the defendants were bona fide purchasers of the land for value, and were in possession under color of title when the trespasses were committed. At the time they took possession the mines were unimproved. They expended large sums of money in their development. They made permanent improvements of great value. Having acted in good faith in the working of the mines and in the removal of the ore, they should be chargeable for the latter only with its value in place: Forsyth *340v. Wells, 6 Wright 291; Herdic v. Young, 5 P. F. Smith 176; Coleman’s Appeal, 12 Id. 262.
. 2. Ore-leave, or the right to dig and take ore, can have no general market value. Its value depends on the position and circumstances of each particular mine; on the quality of the ore ; the cost of mining and preparing it for market; its proximity to the places where it is to be used ; and on the facilities for transportation : Coleman’s Appeal, supra. Hence there was no error in the court charging as it did, substantially, that the value of the ore in place was to be ascertained by deducting the cost of mining, cleansing and delivering the ore in market, from its market value thus delivered — the difference being its value in place. Those costs and expenses only which are reasonable and necessary should be deducted from the gross receipts. The court very correctly said, to the jury, “ no extravagant or unnecessary expenditures, but only such, or so much thereof, as are proper and legitimate expenditures, should be taken into account in ascertaining the real or- legitimate cost of mining, or the value of the ore in place.”
We discover no error in the mode of proving the necessary costs and expenses of operating the mines. Due regard should always, be had to the usual and ordinary manner of conducting the particular business in question. Each branch of industry has its usages and its practices. The work of mining is one of magnitude. It requires the employment of many men. Laborers, overseers, superintendents and operatives must perform their allotted parts. The keeping of a pay-roll is a usual and convenient practice. It furnishes a prompt and concise method oHmaking a daily record of current expenses. Confirmed, as its correctness was in this case, by the testimony of the operator and superintendent, it was clearly evidence proper to submit to the jury of the sums expended in operating the mines. Its effect was properly guarded and restricted by the learned judge.
3. The action for mesne profits is equitable in its character: Morrison v. Robinson, 7 Casey 456; Zimmerman v. Eshbach, 3 Harris 417; Kille et al. v. Ege et al, 1 Norris 102. Hence a bona fide occupant, under claim of title, who has made permanent and valuable improvements, may show' them to be a full compensation for the use of the premises: Morrison v. Robinson, supra; Kille v. Ege, supra.
The criterion of a fixture depends on the business for which the premises’ are used. A fixture in a manufactory, mill or colliery may have no adaptation to many other kinds of business. Although not attached, yet, if it be designed for the convenience of trade on the premises, and be so used, or subject to be called into use at any time, it becomes a fixture. If the article is indispensable in carrying on the specific business, it becomes a part of the realty: Voorhis v. Freeman, 2 W. & S. 116; Pyle v. Pennock, Id. 390. *341This rule, however, does not prevent a tenant, who erects fixtures for the benefit of his trade or business, from removing them from the demised premises within his term. The question here is between persons who were hostile claimants to the land. As between them, all the machinery and implements necessarily used in working the mines became a part of the realty. There was therefore no error in.the court charging, “whether fast or loose, all the machinery of an ore-bank which is necessary to constitute it such, and without which it .would not be an ore-bank equipped and ready for use as such, are a part of the freehold, and the recovery of the land by the plaintiffs in the action of ejectment gave to them the ore-banks on it, with all the machinery, whether fast or loose, necessary to constitute them such equipped and ready for use.” That some machinery was essentially necessary to raise the ore and prepare it for market is very manifest. It was therefore proper to show what machinery was actually used for that purpose, and to submit its necessity and value to the jury. The evidence was rightly received.
The defendants are entitled to an' allowance for such improvements only as are of a lasting and permanent character, and which gave a permanently increased value to the land. This is substantially the third point submitted by the plaintiffs and affirmed by the court. We see no error in the qualification that the increased value may be of limited .duration. In answer to the plaintiffs’ fifth point, the court said if they “were for temporary use only, and not structures of a lasting and permanent character, then they are not such improvements as entitle defendants to credit against the plaintiffs’ demand.” An examination of the answers to the numerous points presented to the court fails to discover any error. All questions relating to the permanency of improvements and of value to the premises were correctly answered.
By the recovery of the land the plaintiffs also recovered all the fixtures thereon put there by the defendants or their lessees. By the execution of the writ of habere facias possessionem the plaintiffs were put in possession thereof. Right of property and actual possession were thus united in them. The right of the defendants to their equitable defence then became fixed. That right could not be impaired by the plaintiffs afterwards permitting the former lessees of the defendants to remove a portion of the machinery. Such a voluntary relinquishment by the plaintiffs of their property to those having no right thereto, either with or without consideration, could not affect the rights of the defendants, who were not a party to the transaction.
■ Inasmuch as there was ample evidence of increased value to the premises by reason of the machinery and improvements, the court committed no error in permitting the defendants to send out a statement with the jury: Blight's Executors v. Ewing, 2 Casey 135.
*342The case was well and carefully tried. The law was clearly and accurately stated by the learned judge. Substantial justice appears to have been reached; therefore
Judgment affirmed.