SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES: (Policies)	3 Months Ended
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES: (Policies)	Mar. 31, 2018
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES:
Revenue recognition	Revenue recognition - The Company adopted ASC 606, Revenue from Contracts with Customers, effective January 1, 2018. The Company’s revenue consists of product revenue resulting from the sale of copper and non-copper products, such as molybdenum, silver, zinc, lead and gold. The Company accounts for a contract with a customer when there is a legally enforceable contract between the Company and the customer, the rights of the parties are identified, the contract has commercial substance, and collectability of the contract consideration is probable. The Company’s revenues are measured based on consideration specified in the contract with each customer. The Company’s marketing strategy and annual sales planning emphasize developing and maintaining long-term customer relationships. Generally, 80% to 90% of the Company’s metal production is sold under annual or longer-term contracts. The Company considers each contract to be a single performance obligation, represented by the delivery of a series of distinct goods that are substantially the same, with the same pattern of transfer to the Company’s customers. Accordingly, the Company recognizes revenues for each contract over a period of time, applying the invoice practical expedient. The Company considers that is has a right to consideration from its customers in an amount that corresponds directly to the value transferred to those customers, for which reason it believes that this method is a faithful depiction of the transfer of goods to its customers. Because the duration of the majority of these contracts is one year or more, and because the Company has applied the invoice practical expedient, it does not disclose the remaining performance obligations as of the end of each reporting period. The remainder of the Company’s revenues are generated by spot sales that are recognized at a point in time. Under both sales models, revenue is recognized as the performance obligations are satisfied, when the Company transfers control of the goods title passes to the customer. Considering the International Commercial Terms (incoterms) utilized by the Company, control is transferred generally upon the completion of loading the material at the point of origin. This is the point at which the customer obtains legal title to the product as well as the ability to direct the use of and obtain substantially all of the remaining benefits of ownership of the asset. Additionally, payment is generally due upon the delivery of the shipping and title documents at the point of origin. Copper and non-copper revenues are measured based on the monthly average of prevailing commodity prices according to the terms of the contracts. The Company provides allowances for doubtful accounts based upon historical bad debt and claims experience and periodic evaluation of specific customer accounts. Substantially all of the Company’s sales are made under cost and freight, or cost, insurance and freight incoterms, whereby the Company is responsible for providing shipping and insurance after control of the inventory has been transferred to the customer. Per the terms of the Company’s contracts, these services are not distinct within the context of the contract, as they are not separately identifiable from other promises in the contract. It is the Company policy and it has a long-standing history of arranging and providing shipping and insurance services to its customers. Accordingly, shipping and insurance are not considered separate performance obligations. Furthermore, the Company considered the impact of the shipping and insurance services on the determination of when control is transferred to its customers. It has concluded that the terms of these services do not impact its customers’ ability to sell, pledge, or otherwise use the products in shipment. As well, there is a small likelihood and minimal history of lost or damaged goods during shipment. Considering these factors, combined with the other indicators of control previously mentioned, the Company has concluded that these services do not impact the determination that control is transferred at the point of origin. For certain of the Company’s sales of copper and molybdenum products, customer contracts allow for pricing based on a month subsequent to shipping, in most cases within the following three months and occasionally in some cases a few additional months. In such cases, revenue is recorded at a provisional price at the time of shipment. The provisionally priced copper sales are adjusted to reflect forward LME or COMEX copper prices at the end of each month until a final adjustment is made to the price of the shipments upon settlement with customers pursuant to the terms of the contract. In the case of molybdenum sales, for which there are no published forward prices, the provisionally priced sales are adjusted to reflect the market prices at the end of each month until a final adjustment is made to the price of the shipments upon settlement with customers pursuant to the terms of the contract. These provisional pricing arrangements are accounted for separately from the contract as an embedded derivative instrument under ASC 815-30 ‘‘Derivatives and Hedging—Cash Flow Hedges.’’ The Company sells copper in concentrate, anode, blister and refined form at industry standard commercial terms. Net sales include the invoiced value of copper, zinc, silver, molybdenum, sulfuric acid and other metals and the corresponding fair value adjustment of the related forward contract of copper and molybdenum.
IMPACT OF NEW ACCOUNTING STANDARDS	IMPACT OF NEW ACCOUNTING STANDARDS During the first quarter of 2018, the FASB issued the following new accounting updates to the Codification: ASU 2018-01: In January 2018, the FASB issued ASU 2018-01 “Leases” (Topic 842). The amendments in this update provide an additional option for the evaluation under Topic 842 of existing or expired land easements that were not accounted for as leases according to the current accounting guidance. The Company is evaluating the impact of this update on its financial statements. ASU 2018-02: In February 2018, the FASB issued ASU 2018-02 “Income Statement — Reporting Comprehensive Income” (Topic 220). This update allows the stranded tax effects that result from the Tax Cuts and Jobs Act to be reclassified from accumulated other comprehensive income to retained earnings. The Company is evaluating the impact of this update on its financial statements. ASU 2018-03: In February 2018, the FASB issued ASU 2018-03 “Technical Corrections and Improvements to Financial Instruments - Overall” (Subtopic 825-10). The FASB undertook this project to address certain issues raised by stakeholders regarding the recognition, measurement and presentation of financial instruments. The Company is evaluating the impact of this update on its financial statements. ASU 2018-04: In March 2018, the FASB issued ASU 2018-04 “Investments — Debt Securities” (Topic 320) and “Regulated Operations” (Topic 980). This update amends several paragraphs that contain SEC guidance in ASC 320 and ASC 980, pursuant to SEC Staff Accounting Bulletin No. 117 and SEC Release No. 33-9273. The Company is evaluating the impact of this update on its financial statements. ASU 2018-05: In March 2018, the FASB issued ASU 2018-05 “Income Taxes” (Topic 740). This update adds several paragraphs that contain SEC guidance in ASC 740, pursuant to SEC Staff Accounting Bulletin No. 118 (“SAB 118”). As previously reported, the Company has adopted SAB 118 and its provisions have been considered in the preparation of its financial statements as of December 31, 2017.