This contract-interpretation case requires an examination of the impact of unanticipated agreements concerning the subject matter of the contract, which agreements were entered into by the party whose performance is deemed to be due. Appellant Cheyenne Mining and Uranium Company (CMU) brought this action against appel-lees Federal-American Partners (FAP) and its member corporations, seeking to rescind a contract for the purchase and sale of certain unpatented mining claims, or in the alternative to enforce the contract’s terms. During the trial to the district court, the judge ruled that appellant’s exhibits, offered to show bad faith on the part of FAP, were inadmissible. .Following three and one-half days of testimony, the trial court took the matter under advisement and subsequently entered a judgment awarding CMU $3,306 under the contract provisions, plus accrued interest and costs. On appeal, CMU contends that the trial court’s interpretation of the contract improperly limited its award and further asserts that the trial court erred in refusing to admit pertinent evidence and to grant rescission.
We will reverse.
On November 1, 1957, CMU as “Owner,” together with named individuals designated “Locators,” entered into a “Contract of Purchase and Sale” with Vitro Minerals Corporation as “Purchaser” for the conveyance of unpatented uranium mining claims located in Natrona County. The contract was subsequently assigned to FAP, which concedes to being bound by its terms.
In executing the contract, the owner and locators agreed to “convey, quitclaim and assign” all interest in and to the mining claims to the purchaser, “under and upon, nevertheless, the terms and conditions hereinafter set forth.” The terms and conditions set forth in paragraph 4, relating to owner’s participation, are pertinent to this appeal:
“4. OWNER’S PARTICIPATION: For and in consideration of the Assignment and Conveyance to Purchaser of Owner[’]s interest, the Purchaser covenants and agrees to pay to the Owner, its successors, assigns or legal representatives, a sum constituting forty per cent (40%) of the annual net profits from all uranium, vanadium and other associated minerals and ores mined, produced and sold from the property, computed in accordance with and under the terms and conditions hereinafter set forth. In addition, it promises and agrees to perform a minimum of 20,000 feet of drilling upon the property at such locations and in such manner as may be deemed advisable by it within twelve months after the 15th of July, 1957.
“a. COMPUTATION: Net profits shall be arrived at by deducting from gross proceeds those items listed upon the schedule of deductions hereto attached as Exhibit A[1]
“b. BASIS FOR GROSS PROCEEDS: Gross proceeds shall include the proceeds from ore sold based upon prices established in Circular 5 Revised, or, in event that such schedule should be supplemented by another, the schedule (hen in effect or the market price then current for such ore; it shall not include the proceeds from the operation of any concentration or milling opera*68tion or benefication process which might be erected upon the property or erected, owned or operated by the Purchaser.
“c. TIME FOR PAYMENT. Distribution of net profit shall be made quarterly and within thirty days after the close of such quarter. For the purpose of such distributions, such quarterly periods shall end on the last day of March, June, September and December of each year. The Purchaser at its option, may make such distributions at the end of each month. If the quarterly distributions exceed the Owner[’]s share of the annual net profits as determined at the end of each calendar year, Owner shall repay Purchaser such excess or Purchaser may deduct such excess from future payments due Owner.
“d. ACCOUNTING: Each distribution of net profit shall be accompanied by a true, correct and complete accounting statement, showing the factors entering into the distribution made, all in accordance with standard accounting practices employed under the schedule hereto attached and with the terms of this instrument.
“GENERAL: The provisions hereinabove made with respect to the Locators for availability and examination of records, statement, or Declaration of Interest, and time and responsibility for payment, shall be applicable to the distribution of net profit to the Owner.
“f. MINIMUM PAYMENT: During this agreement, Purchaser will work the property diligently and in minerlike fashion with the object of discovering, producing and marketing commercial ores. Within sixty (60) days after Purchaser develops a commercial deposit of ore ready for extraction, it shall pay Owner a minimum of Five Hundred Dollars ($500.00) per month as net profits therefrom, which payments shall be a credit upon any and all of Owner[’]s share of net profits as herein defined. Such minimum payments shall cease when such ore body has been exhausted unless another ore body has been developed and made ready for extraction. * * *” (Emphasis added.)
On April 27, 1973, FAP entered into two agreements with Tennessee Valley Authority (TVA), which agreements provided for the development of numerous mining properties owned or controlled by FAP in the Gas Hills Mining District, including the claims subject to the 40% annual-net-profits interest held by CMU. The principal agreement, designated “Mining Lease Agreement,” contains the following grant:
“A. For and in consideration of good and valuable consideration and of the covenants and agreements herein contained, Lessor [FAP] hereby grants to the Lessee [TVA] and the Lessee’s successors and assigns for the term hereinafter provided the exclusive right to explore, develop, mine, extract and remove from the Mining Properties all uranium and other fissionable source materials, including associated minerals, in, on, under, or upon the said properties and thereafter to retain all right title and interest in and to all such severed minerals. Lessee shall also have the right to use so much of the surface of the Mining Properties as may be reasonably required to conduct exploration, development, mining and milling activities.”
As consideration to FAP, the agreement specifies in Article III the following royalty payments:
“Lessee agrees to pay Lessor the following royalties:
“A. As concerns 6,000,000 pounds of ⅞08 contained in reserves upon the Mining Properties and presently classified as Indicated Ore, Lessee shall pay Lessor Seven Million dollars ($7,000,000), payable:
“(1) Four Million Five Hundred Thousand dollars ($4,500,000) at closing; and
“(2) Two Million Five Hundred Thousand dollars ($2,500,000) on or before January 1, 1979.
“B. As concerns 2,400,000 pounds of U3O8 contained in reserves presently classified as Inferred Ore (over and *69above the said 6,000,000 pounds referred to in A above), an amount equal to sixty-two and one half cents (62½⅞:) per pound of UgOg in that category determined by March 31, 1975, to be Indicated Ore, up to and until a maximum of One Million Five Hundred Thousand dollars ($1,500,-000) is owed to Lessor. Said royalty payment shall be made on or before March 31, 1975. * * *
“C. A payment equal to fifty percent (50%) of the amount by which the market price for U3O8 concentrate exceeds the production cost of such concentrates, which cost shall include payments made pursuant to paragraphs A and B above, royalties and similar payments (excluding, however, the royalty to be paid pursuant to this Article III, paragraph C) all outlays by TYA from date of closing to date of delivery of ⅞(⅛ concentrates, plus interest at the rate of seven and one half percent {1⅝%) per annum, on a non-compounded basis on the above costs, allocated on a per pound basis of delivered U3O8 concentrates. * * *”
To implement the development of the mining properties contemplated by the mining lease agreement, the parties agreed to a working agreement embodied in the “Interim Agreement.” Under this agreement FAP, as contractor, assumed the exclusive right and duty to manage the properties described in the mining lease, to perform exploratory work, and to mill the extracted ore — all on behalf of TVA and at TVA’s expense.2 The interim agreement was replaced one year later by the “Exploration and Milling Agreement, Definitive Agreement,” which more fully describes FAP’s duties as contractor and the procedure for payment of costs by TVA. The agreement provides that “all costs incurred in the performance of Authorized Operations * * * shall be at TVA’s expense.” In describing the end product of these operations, the definitive agreement provides:
“Title to all ore from the Mining Properties fed into Contractor’s mill, and all U3O8 Concentrate derived therefrom, shall remain in TVA.”
In October, 1978, FAP began to mine the subject properties in which CMU holds an interest. Between December, 1979, and June, 1980, FAP paid CMU a total of $9,000 in minimum payments called for under paragraph 4f of the contract of purchase and sale. CMU was dissatisfied, however, with the accounting information furnished to it by FAP and in March, 1981, initiated this action. CMU first learned of the series of agreements between FAP and TVA at that time.
The trial court determined that CMU was entitled to 40% of the annual net profits attributable to uranium ore produced from the subject properties between 1978 and 1981. Net profits were calculated by deducting from gross proceeds those items specified in Schedule A,3 pursuant to paragraph 4a of the contract of purchase and sale. The figures for annual gross proceeds due to uranium ore were extrapolated from the market values of ⅝08 concentrate, using one of the three alternative methods of calculation presented by FAP at trial. The court adopted appellees’ method which updated Atomic Energy Commission Circular 5 by incorporating current values of U3O8 concentrate. This method followed the contract, according to the court, and resulted in CMU receiving *70its appropriate compensation of $3,306 in addition to the $9,000 in minimum payments already received.
CMU challenges the trial court’s conclusion in two respects: (1) the calculation of net profits based solely on the tonnage of uranium ore mined and milled between 1978 and 1981 denies CMU the right to participate fully in its pro-rata share of the $7,000,000 in advance royalties paid to FAP under Article IIIA of the mining lease agreement; and (2) the calculation of gross proceeds attributable to uranium ore using a formula purportedly designed to escalate Circular 5 to current values is contrary to the express terms of the contract and to the intent of the parties to apportion to CMU its fair share of the profits derived from the uranium claims. In addition, CMU asserts that it is entitled to rescind the contract for purchase and sale as a result of FAP’s bad faith in failing to proceed in a diligent and minerlike fashion to produce commercial ores, failing to account and failing to timely distribute proceeds. We will hold that, under the terms of the contract of purchase and sale, CMU became entitled to participate in its pro-rata share of the $7,000,000 in advance royalties when they were paid to FAP and, further, that a proper calculation of gross proceeds attributable to uranium ore requires deducting commercial milling rates from the market value of U3Os concentrate. Finally, we will hold that the trial court erred in denying CMU the opportunity to present evidence going to the bad-faith performance of FAP for the purpose of establishing grounds for rescission.
CONTRACT INTERPRETATION
We repeated the basic purpose and general rules of contract interpretation in Amoco Production Company v. Stauffer Chemical Company of Wyoming, Wyo., 612 P.2d 463, 465 (1980):
“Our basic purpose in construing or interpreting a contract is to determine the intention and understanding of the parties. Fuchs v. Goe, 62 Wyo. 134, 163 P.2d 783 (1945); Shellhart v. Axford, Wyo., 485 P.2d 1031 (1971); Oregon Short Line Railroad Company v. Idaho Stockyards Company, 12 Utah 2d 205, 364 P.2d 826 (1961). If the contract is in writing and the language is clear and unambiguous, the intention is to be secured from the words of the contract. Pilcher v. Hamm, Wyo., 351 P.2d 1041 (1960); Fuchs v. Goe, supra; Hollabaugh v. Kolbet, Wyo., 604 P.2d 1359 (1980); Wyoming Bank and Trust Company v. Waugh, Wyo., 606 P.2d 725 (1980). And the contract as a whole should be considered, with each part being read in light of all other parts. Shepard v. Top Hat Land & Cattle Co., Wyo., 560 P.2d 730 (1977); Rossi v. Percifield, Wyo., 527 P.2d 819 (1974); Shellhart v. Axford, supra; Quin Blair Enterprises, Inc. v. Julien Construction Company, Wyo., 597 P.2d 945 (1979). The interpretation and construction is done by the court as a matter of law. Hollabaugh v. Kolbet, supra; Bulis v. Wells, Wyo., 565 P.2d 487 (1977); Shepard v. Top Hat Land & Cattle Co., supra.”
A more recent case to the same effect is Rouse v. Munroe, Wyo., 658 P.2d 74 (1983).
In interpreting a conveyance of a mineral interest, the court may augment these general rules by considering pertinent, extrinsic factors. In Dawson v. Meike, Wyo., 508 P.2d 15, 18 (1973), we said:
“ * * * [W]e find no fault with * * * the authority of Houghton v. Thompson, 57 Wyo. 196, 115 P.2d 654, that to interpret a contract for the conveyance of an interest in oil and gas the court should consider not only the terms of the writing but also the surrounding circumstances, attendant facts showing the relations of the parties, the nature and situation of the subject matter, and the apparent purpose of making the contract.
See also Picard v. Richards, Wyo., 366 P.2d 119 (1961). The basic purpose of contract interpretation — to determine the intention of the parties — remains the same, *71however, regardless of the form of the agreement. Dawson v. Meike, supra.
With the foregoing principles in mind, we attempt to ascertain the probable intention of the parties in entering into the contract involved in this appeal, had they envisioned the manner in which the uranium ore was actually transferred — that is, all rights to the ore were sold prior to its being mined and produced. We note that no dispute as to any material fact exists between the parties. All mining and milling data were supplied by FAP and accepted by CMU at face value. Accordingly, our resolution of the issues on appeal turns solely upon the proper means of implementing the original contract in light of the subsequent disposition of its subject property.
ADVANCE ROYALTIES
The mining lease agreement dated April 27, 1973, provides in Article III for TVA to pay FAP $7,000,000 for 6,000,000 pounds of U3O8 contained in reserves classified as indicated ore, or $1.17 (rounded to the nearest cent) per pound of contained U3O8. These royalties were payable in two lump sums — $4,500,000 at closing and $2,500,000 on or before January 1, 1979. The nature of these payments as advance royalties is made clear in Article IIIC of the mining lease agreement, which specifies that the $7,000,000 is to be amortized as a “production cost” in computing the proceeds owed to FAP on each pound of delivered ⅞(⅛ concentrate. Thus, FAP retains the advance royalties, regardless of the success or failure of a particular mining claim, but royalty payments on delivered U3O8 are reduced by $1.17 (rounded to the nearest cent) per pound until 6,000,000 pounds of U3O8 have been profitably recovered.
Testimony at trial indicated that of the 6,000,000 pounds of contained U308 specified in Article IIIA of the mining lease agreement, 163,500 pounds were located in those properties subject to CMU’s 40% interest. CMU contended at trial and urges on appeal that, under the 1957 contract of purchase and sale, it is entitled to a 40% share of $190,739,4 or $76,295.
The contract of purchase and sale provides that CMU is entitled to 40% of the annual net profits from all uranium “mined, produced and sold from the property.” Under the express language of the contract, FAP’s obligation to distribute net profits is conditioned upon the sale of mined and produced ore. Accordingly, ap-pellees assert that CMU is not entitled to participate in the advance royalties which were paid prior to mining, production and sale of uranium ore.
The language in the mining lease agreement, as well as surrounding circumstances, leads us to conclude that the agreement constituted a sale of ore to TVA, notwithstanding the document’s designation as a lease. Under the mining lease agreement FAP granted to TVA
«* * * exclusive right to explore, develop, mine, extract and remove from the Mining Properties all uranium and other fissionable source materials, * * ⅜ and thereafter to retain all right title and interest in and to all such severed minerals.” (Emphasis added.)
The Pennsylvania Supreme Court in Gilberton Fuels, Inc. v. Philadelphia & Reading Coal & Iron Co., 342 Pa. 192, 20 A.2d 217 (1941), construed similar language in a 15-year lease as effecting a sale of coal in place:
“The instrument in the instant case contemplated the exhaustion of the coal in the land. That is, it conveyed all the coal and gave the right to mine and take away without limit. It is hard to differentiate this from a sale. In our opinion the defendant held title to the coal in place for all purposes * * *.” 20 A.2d at 221.
We find this reasoning sound and applicable to the instant case. FAP conveyed to TVA the right to mine, remove, and retain title to all uranium. It is difficult to differentiate this transaction from a “sale,” notwithstanding the argument by appellees *72that the federal government owned the minerals in question prior to their severance from the ground. No other sale of uranium in any form was ever made to TVA from appellant’s property. TVA simply retained title to the end product — milled uranium — for use as fuel. We conclude, therefore, that the mining lease agreement effected a sale of the uranium ore to TVA.
Next, we must consider whether FAP sold TVA “mined [and] produced” ore, so as to trigger FAP’s obligation to pay CMU 40% of the resulting profits. Under the interim agreement and the subsequently executed definitive agreement, FAP acted as contractor on behalf of TVA, developing and milling the ore at TVA’s convenience and expense. The entire series of agreements between FAP and TVA contemplate the mining and production of the ore which, as we have seen, was sold to TVA. At the moment that the mining lease agreement and the interim agreement were signed, FAP was under a contractual obligation to mine and produce ore from the subject properties. The physical performance of these obligations is immaterial to our purpose of determining whether FAP owed CMU a portion of the advance royalties. The important point is that FAP promised to develop the ore for TVA, subject to sanctions for failure to do so. Therefore, in light of the terms of the writings, the relationship of the parties, the nature and situation of the subject matter and the purpose of making the agreements, Dawson v. Meike, supra, we hold that the mining lease agreement and the interim agreement constituted a sale of mined and produced ore such that FAP became obligated to pay CMU its share of the proceeds resulting from those transactions.
FAP also advances the argument, successful at trial, that its investment in the mining properties (for example, acquisition and exploration costs) prior to the 1973 mining lease agreement with TVA depleted the advance royalties so that, after discounting to present value, nothing remained to pay CMU. It is clear, however, that, regardless of legitimate investment costs associated with other properties subject to the mining lease agreement, no payments were made to CMU for acquisition purposes. Furthermore, no documentation so much as suggests that the advance royalties attributable to the properties in question were consumed by costs listed on Schedule A of the contract of purchase and sale and incurred by FAP prior to 1973. In contrast, the evidence submitted by FAP shows that after 1973 approximately $17,-000,000 were expended to develop the subject properties over and above the actual mining costs from 1978 to 1981.
Paragraph 4d of the contract of purchase and sale requires FAP to furnish complete accounting statements showing factors that affected the distribution of profits. In view of FAP’s failure to offer any documentation whatsoever as to the allocation of the advance profits attributable to the properties in question, we must conclude that, absent a showing to the contrary on remand, CMU became entitled to 40% of those royalties upon their payment to FAP under the mining lease agreement.
ANNUAL NET PROFITS
The parties disagree as to the proper method of determining gross proceeds attributable to the uranium ore after completion of the milling process. The contract of purchase and sale provides that gross proceeds shall be
“ * * * based upon prices established in Circular 5 Revised, or, in event that such schedule should be supplemented by another, the schedule then in effect or the market price then current for such ore * * * }}
The contract expressly excludes from gross proceeds any proceeds from milling the ore into U3O8 concentrate, or yellow cake, as it is commonly called. The parties’ dispute results from the fact that none of the methods specified in the 1957 contract for computing gross proceeds works to extrapolate ore proceeds from the market value of yellow cake between 1978 and 1981.
Circular 5 listed prices that the Atomic Energy Commission would pay for various *73grades of unprocessed uranium ore based on a value of $8 per pound of processed U3O8 concentrate. Neither Circular 5 nor a supplemental circular was in effect when the ore involved here was mined and milled, since the abolishment of the Atomic Energy Commission in 19745 rendered these schedules obsolete. In addition, no market for unprocessed ore existed in the Gas Hills district at the relevant times, making the contract’s alternate basis for determining gross proceeds — “the market price then current for such ore” — inapplicable.
In an effort to resolve this dilemma, FAP submitted to the trial court three different methods for determining gross proceeds. The first method, and the one accepted by the trial court as consistent with the contract, purported to update Circular 5 to reflect the values of unprocessed ore based on values of U3O8 which ranged from $36 to $45.34 per pound at the times relevant here. Gross proceeds were thus calculated by multiplying Circular 5 values for raw ore by the factor by which the value of U3O8 had increased since the circular went into effect.6
This method assumes that the costs associated with mining increased proportionally to those costs associated with milling. We find this assumption erroneous since it ignores the effects of technological advances on both procedures, their respective labor intensities, and the degree of skill required in each operation. Therefore, we conclude that the gross-proceeds figures obtained from Circular 5, as modified, were not sufficiently reliable to permit the trial court to award CMU its proper share of profits.
The second theory advanced by FAP for determining gross proceeds involved the averaging of three ore purchase-price schedules compiled in 1976. Two of the schedules refer to ore mined in Utah, and one lists standard prices. We agree with the trial court as to the undesirability of this method of arriving at gross proceeds, since none of the schedules concerns ore mined in the Gas Hills district and all predate the mining of the subject properties.
The third alternative proposed by FAP we find to be the most appropriate means of calculating CMU’s fair share of profits due to mined uranium ore. This method computes gross proceeds by deducting commercial milling rates from the sales value of yellow cake. The base commercial milling rate was determined to be $23/ton of ore by appellees’ expert witness who had researched the matter in 1978 for a mining company located in the Gas Hills district. For purposes of calculation, the base rate was escalated at 8% per year from 1978. This method awards FAP commercial profits for its milling operation, consistent with the contract of purchase and sale, based upon milling rates that are typical of other mills operating at that time.
We approve of this method as a reliable means of implementing the intent of the parties to compensate CMU out of proceeds derived from the sale of processed ore, exclusive of milling profits. Where the market for disposing of a royalty owner’s minerals changes from that originally contemplated by the parties, the court’s duty is to construe the royalty agreement fairly so as to effectuate the intent of the parties. LeCuno Oil Company v. Smith, Tex.Civ.App., 306 S.W.2d 190 (1957).
In view of our holding that CMU is entitled to participate in the advance royalties paid to FAP, on remand the amount of such royalties proportionate to each pound of recovered ⅞08 must be deducted from annual net profits payable to CMU.
EVIDENCE ESTABLISHING GROUNDS FOR RESCISSION OF THE CONTRACT OF PURCHASE AND SALE
The trial court refused to admit evidence offered by CMU to prove bad faith on the part of FAP in breaching the con*74tract of purchase and sale. Such evidence, appellant contends, would have established a basis upon which to rescind the contract.
FAP takes the position on appeal that the contract of purchase and sale is a deed transferring title, which instrument is not subject to forfeiture absent some express provision such as a right of re-entry or a power of termination. We cannot agree.
A number of courts have held that a conveyance of a mineral interest in consideration of royalties on production amounts to a lease and may be cancelled upon a proper showing. The Kentucky Court of Appeals construed such an agreement in Kentucky Rock Asphalt Co. v. Milliner, 234 Ky. 217, 27 S.W.2d 937 (1930). There, in consideration of $5 plus future royalties, appellee had granted “ ‘all of his right, title and interest, in and to all deposits of oil, bitumen and their products.’ ” 27 S.W.2d at 937. Thirty-nine years later the grantee had made no effort to develop the property. In holding that the instrument, regardless of its label, was intended as a lease and, therefore, was subject to forfeiture, the court quoted extensively from Eastern Kentucky Mineral & Timber Co. v. Swann-Day Lumber Co., 148 Ky. 82, 146 S.W. 438, 46 L.R.A.(N.S.) 672 (1912):
“‘ * * * In an attempt to ascertain whether a deed like this was intended by the parties to be a conveyance in fee simple, or only a contract or lease under which the grantees must begin operations within a reasonable time, there is no feature entitled to more weight than the one relating to the consideration and the manner of its payment. There is and should be a marked difference between the construction and effect of a conveyance of timber and minerals, or indeed any interest in land, for a stipulated consideration, payable in cash or in secured notes or in some other valuable property, and the construction and effect of a conveyance in consideration of a royalty or per cent., to be paid out of the income derived by the grantees from the property conveyed. * * * When the consideration has been fully satisfied, and the grantor has parted with his estate, the transaction between the parties is a closed incident. The grantor has no further interest or concern in the property conveyed. But a very different situation is presented when the only consideration the grantor is to receive is a per cent, of the profits the grantee may realize from the development of the estate. Under such a contract the consideration is a continuing one, to be paid only by the labor of the grantee in the development of the property. The grantor has a continuing interest in the estate conveyed, the transaction between the parties is not a closed incident, and the grantee is not at liberty to do with the property as he pleases. He cannot use or fail to use it to the prejudice of the grantor who has rights that must be respected.’ ” 27 S.W.2d at 938-939.
See also Davis v. Mann, 234 F.2d 553, 558 (10th Cir.1956); Crain v. Pure Oil Co., 25 F.2d 824, 830 (8th Cir.1928); Tennessee Oil, Gas & Mineral Co. v. Brown, 131 F. 696, 702-703 (6th Cir.1904).
Under the contract of purchase and sale in the instant case, the consideration is a continuing one. FAP’s ongoing obligations to CMU include diligent development and sale of ore, the payment of minimum monthly sums once a commercial body of ore is ready for extraction, the timely distribution of 40% of annual net profits, and accountings. We conclude that such an agreement is properly denominated a “lease” and may be cancelled upon a showing of a material breach.
In Vitro Minerals Corporation v. Shoni Uranium Corporation, Wyo., 386 P.2d 938 (1963), we considered the grounds necessary to rescind a mining lease, which contained a clause expressly providing for forfeiture under certain circumstances. We said that evidence going to the bad faith of the lessee is admissible and relevant in establishing grounds for rescission, 386 P.2d at 940. We quoted with approval from Annot., 60 A.L.R. 901, 925:
“ ‘But it has been held that forfeitures, even though expressly provided in a min*75ing lease, for the failure to develop and properly mine, are even less favored than are forfeitures generally, much being left to the discretion of the operator. In the absence of evidence of fraud or bad faith, such forfeitures will not be enforced; for a breach of a covenant properly to work the premises, especially if due to a mistake of judgment only, the wilful default or bad faith of the lessee not being shown, a forfeiture of the lease will not be decreed. * * * ’ ” 386 P.2d at 942.
We hold that evidence of bad faith and material breach is admissible to establish grounds for rescission, should CMU choose to pursue such a remedy on remand.
Reversed and remanded to the district court for proceedings consistent with this opinion.
. Schedule A lists 14 items to be deducted from gross proceeds in computing net profits. These items include the purchaser’s costs of survey and exploration, development, transportation, management, labor, supplies, maintenance of equipment, insurance, and depreciation.
. The interim agreement contemplated its replacement by an exploration and milling agreement, under which TVA would establish an operating account to cover allowable costs:
"The definitive Exploration and Milling Agreement shall provide that TVA will deposit sufficient sums in an Operating Account from which Contractor may withdraw sums on an accrual basis to cover allowable costs for which TVA is liable pursuant to the definitive Agreement. Until such time as the definitive Agreement is executed, Contractor shall pay all sums incurred in the performance of its obligations under this contract, including costs of milling TVA ore, making lease rental payments to third parties, and all other costs, from its own funds and shall submit detailed monthly invoices to TVA covering allowable costs incurred during the month in question. Payment for such costs shall be made by TVA within thirty (30) days.”
. Note 1, supra.
. $1.1666/lb. of U308 x 163,500 lbs. of U308 = $190,739.
. Pub.L. 93-438, Title I, § 104(a), October 11, 1974, 88 Stat. 1237.
. For example, the multiplication factor would be 5.335 where the current market value of U308 is $42.68 per pound and the Circular 5 value of U308 is $8 per pound.