Plaintiff Sharon Steel Corporation brought this diversity action against defendant Lakeshore, Inc. when a mining sheave wheel shaft used in plaintiff’s business.broke. Plaintiff’s corporate predecessor had purchased this product from defendant. A district court jury answered specific interrogatories and imposed liability on defendant on theories of strict liability and negligence, finding total damages of $267,210. The trial court allowed prejudgment interest, on the award. Defendant appeals the decision, asserting that plaintiff did not present sufficient evidence to establish a cause of action based on either strict liability or negligence, that plaintiff’s damages were for economic loss not recoverable under either theory, and that, in any event, plaintiff is not entitled to prejudgment interest.
After examining the record we have concluded there was sufficient evidence to support submitting the strict liability question to the jury. We recently held, however, that New Mexico law does not permit recovery of economic loss in products liability cases tried on the basis of strict liability.
Colonial Park Country Club v. Joan of Arc,
I
In order to understand this case, a basic knowledge of the configuration of the mining equipment involved is helpful. At plaintiff’s Bayard, New Mexico underground mine there is an eighty-five foot metal structure known as a head frame above the mine shaft. This head frame *853 supports four nine-feet diameter sheave wheels. These sheave wheels in turn support hoist cables that raise and lower the mining skips that carry the mined copper. As the sheave wheels turn at the top of the head frame, the hoist cables are drawn or released from large cylindrical drums. The hoist house contains large motors that turn the drums which wind the hoist cable. Therefore the sheave wheels guide the hoist cables into the mine and into the hoist house.
On March 5, 1981, a sheave wheel shaft that plaintiffs predecessor purchased approximately fifteen years earlier broke at the mine. This shaft had acted as an axle supporting the sheave wheel in the head frame. When the shaft broke, the sheave wheel fell approximately fifty to sixty feet from the head frame to a parking lot below, and the hoist cable, pulling a loaded skip, fell approximately 600 feet down the mine shaft. As the skip fell, its safety devices gouged hardwood guides along the mine shaft.
The dispute in this case concerns the cause of the sheave wheel shaft failure. Plaintiff argued that the break occurred because defendant “mismachined” the shaft. Defendant’s plan for the shaft required two “step-downs” or decreases in radii, with a quarter-inch minimum radius at the first step-down. Instead of adhering to its plan, defendant built the shaft with a Vi6th inch radius at the first step-down. This step-down is the place at which the shaft broke. The dispute on the negligence theory is whether defendant was negligent in manufacturing the shaft with the Vi6 inch radius. Defendant presented to the jury evidence that plaintiff’s misuse of the equipment caused the accident. Defendant argued that plaintiff caused the shaft to break by overloading the system, by not properly maintaining the braking apparatus for the system, and by not properly maintaining the ball bearings that allowed the shaft and the wheel to rotate.
Defendant argues that the district court should have directed a verdict in its favor on the issue of negligence. Although New Mexico law governs the substantive law questions in this diversity action, federal law controls the procedural issue of whether the plaintiff has presented sufficient evidence to withstand a motion for a directed verdict.
See, e.g., Martin v. Unit Rig & Equipment Co.,
“Fed.R.Civ. 50(a), which provides for a motion for a directed verdict, is intended to remove from the jury a case where there is either a ‘complete absence of proof of an issue or issues material to the cause of action’ or where 'there are no controverted issues of fact upon which reasonable men could differ.’ 5A Moore’s Federal Practice 150.02[1], at 50-20 (2d ed. 1982). To ensure that the court’s exercise of discretion does not improperly invade the province of the jury, the court’s discretion to grant a motion for directed verdict is limited in several respects. Most importantly, the court must view the evidence in the light most favorable to the non-moving party. Wylie v. Ford Motor Company,502 F.2d 1292 , 1294 (10th Cir.1974). Further, the opposing party must be given the ‘benefit of all inferences which the evidence fairly supports, even though contrary inferences might reasonably be drawn.’ New Mexico Savings & Loan Ass’n v. United States Fidelity and Guaranty Co.,454 F.2d 328 , 331 (10th Cir.1972). Moreover, the court is not permitted to consider the credibility of witnesses in reaching its decision, Brady v. Southern Ry. Co.,320 U.S. 476 , 479-80 [64 S.Ct. 232 , 234-35,88 L.Ed. 239 ] (1943); Wright & Miller, Federal Practice and Procedure § 2527, at 560 (1971), nor may a court weigh the evidence or determine where the preponderance of the evidence lies. Wylie v. Ford Motor Company, supra,502 F.2d at 1294 . See Continental Ore Co. v. Union Carbide & Carbon Corp.,370 U.S. 690 , 700-01 [82 S.Ct. 1404 , 1411-12,8 L.Ed.2d 777 ] (1962) (jury weighs contradictory evidence and infer- *854 enees, draws ultímate conclusion, as to facts).”
In order to justify a finding that defendant was negligent in this case, plaintiff must submit some evidence of defendant’s breach of its duty to exercise ordinary care in machining the sheave wheel shaft.
See Fabian v. E.W. Bliss Co.,
II
The jury found in favor of plaintiff for $267,210, representing “all damage sustained,” of which $162,489 was for pecuniary loss. These figures were identical to the claims made by plaintiff on its Exhibit 40 for completed rehabilitation costs, future rehabilitation costs, and increased mining and milling costs. The rehabilitation costs represented costs of replacement of the sheave shaft, costs of repair of the mine shaft, costs of the firm hired to analyze the cause of the failure, and salaries of employees kept on the payroll while the shaft was repaired. The mining and milling costs were plaintiff’s calculations of its losses in the form of decreased production while the underground shaft was repaired based upon assumptions as to production and average costs per pound to mine and mill. Although the New Mexico cases do not discuss directly the issue of the types of damages recoverable under a negligence theory, given the underlying policies stated in the decisions we believe that the New Mexico Supreme Court would allow recovery for the losses plaintiff sustained.
The term “economic loss” developed as a label for the remedy in contract for damages under warranty for a defective product. One commentator on the subject has written that economic loss is “the diminution in the value of the product because it is inferior in quality and does not work for the general purposes for which it was manufactured and sold.” Comment,
Manufacturers’ Liability to Remote Purchasers for “Economic Loss” Damages
— Tort
or Contract?,
114 U.Pa.L.Rev. 539, 541 (1966)
(iquoted in Pennsylvania Glass Sand Corp. v. Caterpillar Tractor Co.,
Chief Justice Traynor in
Seely v. White Motor Co.,
“The distinction that the law has drawn between tort recovery for physical injuries and warranty recovery for economic loss is not arbitrary and does not rest on the ‘luck’ of one plaintiff in having an accident causing physical injury. The distinction rests, rather, on an understanding of the nature of the responsibility a manufacturer must undertake in distributing his products. He can appropriately be held liable for physical injuries caused by defects by requiring his goods to match a standard of safety defined in terms of conditions that create unreasonable risks of harm. He cannot be held for the level' of performance of his products in the consumer’s business unless he agrees that the product was designed to meet the consumer’s demands. A consumer should not be charged at the will of the manufacturer with bearing the risk of physical injury when he buys a product on the market. He can, however, be fairly charged with the risk that the product will not match his economic expectations unless the manufacturer agrees that it will. Even in actions for negligence, a manufacturer’s liability is limited to damages for physical injury and there is no recovery for economic loss alone.”
Plaintiff in this case does not seek a remedy for the product’s failure to meet qualitative expectations. Instead, plaintiff seeks compensation for damages caused by the failure of a negligently manufactured product. We believe that tort law supports recovery of damages that could be characterized as economic loss when, because of a negligently manufactured product, plaintiff is subjected to an unreasonable risk of injury to his person or property.
Pennsylvania Glass Sand Corp. v. Caterpillar Tractor Co.,
In
LeSueur Creamery, Inc. v. Haskon, Inc.,
We can find no case law in New Mexico that precludes plaintiff’s recovery. Two decisions interpreting New Mexico law favor economic loss awards in negligence cases, although they did not involve damages caused by defective products. In
Curtis v. Schwartzman Packing Co.,
The rationale underlying the theory of negligence recovery also supports plaintiff’s damage award. As the New Mexico Court of Appeals said in
Topmiller v. Cain,
III
Defendant argues that the award of prejudgment interest was improper. We interpret New Mexico law to permit a trial court judge to award prejudgment interest in a negligence case when the damages are precisely determinable. The New Mexico Supreme Court in
Board of Education v. Standhardt,
“(1) Except when the plaintiff can and does elect the restitutional measure of *857 recovery, he is entitled to interest upon the amount found due
(a) for the taking or detention of land, chattels or other subjects of property, or the destruction of any legally protected interest in them, when the valuation can be ascertained from established market prices, from the time adopted for their valuation to the time of judg-ment____”
Restatement (Second) of Torts § 913 (1979) (emphasis added).
Our problem with the award of prejudgment interest in the instant case is that we do not believe the damages were ascertainable with reasonable certainty, despite the jury’s acceptance of plaintiff’s figures and its finding that the damages were ascertainable by May 1, 1981. There was much room for argument about the amount of the damages, even for repairs. Plaintiff did not replace merely the broken shaft, the hardwood guides and other damaged items. It replaced the cable, bearings and other parts in accordance with what it considered good practice. With respect to mining and milling costs plaintiff made mathematical calculations based upon presumed production, presumed copper content of ores, and estimates of personnel needs and costs. It presented different calculations to defendant several times during the pendency of the suit. One item included was the cost of hiring plaintiff’s expert’s firm to analyze the cause of the shaft failure, and that firm did not even make its report until December 31, 1981. Determining whether an award of prejudgment interest is proper is a matter of law,
see Navajo Tribe v. Bank of New Mexico,
We affirm the judgment of the district court in all respects except for its award of prejudgment interest. On that issue we reverse and remand for further proceedings consistent with this opinion.
Notes
. N.M.Stat.Ann. § 56-8-4(C) appears to assume the existence of a common law rule permitting interest awards in appropriate cases.
