| (b) | Financial instruments - Initial recognition and subsequent measurement - |
A financial instrument is any contract that gives rise to a financial asset of one entity and a financial liability or equity instrument of another entity.
Initial recognition and measurement -
Financial assets are classified, at initial recognition, as financial assets at fair value through profit or loss, loans and receivables, held-to-maturity investments, available-for-sale financial assets, or derivatives designated as hedging instruments in an effective hedge, as appropriate. All financial assets are recognized initially at fair value plus, in the case of financial assets not recorded at fair value through profit or loss, transaction costs that are attributable to the acquisition of the financial asset.
Subsequent measurement -
For purposes of subsequent measurement, financial assets are classified in four categories:
| - | Financial assets at fair value through profit or loss. |
| - | Held-to-maturity investments. |
| - | Available-for-sale financial investments. |
Financial assets at fair value through profit or loss -
Financial assets at fair value through profit or loss include financial assets held for trading and financial assets designated upon initial recognition at fair value through profit or loss. Financial assets are classified as held for trading if they are acquired for the purpose of selling or repurchasing in the near term. Derivatives, including separated embedded derivatives, are also classified as held for trading unless they are designated as effective hedging instruments as defined by IAS 39.
Financial assets at fair value through profit or loss are carried in the consolidated statements of financial position at fair value with net changes in fair value presented as finance costs (negative changes) or finance revenue (positive changes) in the consolidated statements of profit or loss.
Derivatives embedded in host contracts are accounted for as separate derivatives and recorded at fair value if their economic characteristics and risks are not closely related to those of the host contracts and the host contracts are not held for trading or designated at fair value though profit or loss. These embedded derivatives are measured at fair value, with changes in fair value recognized in profit or loss.
Loans and receivables -
Loans and receivables are non-derivative financial assets with fixed or determinable payments that are not quoted in an active market. After initial measurement, such financial assets are subsequently measured at amortized cost using the effective interest rate method, less impairment. The losses arising from impairment are recognized in the consolidated statements of profit or loss.
This category generally applies to trade and other receivables, net.
Held-to-maturity investments -
Non-derivative financial assets with fixed or determinable payments and fixed maturities are classified as held to maturity when the Group has the positive intention and ability to hold them to maturity. The Group did not have any held-to-maturity investment as of December 31, 2017 and 2016.
Available-for-sale financial assets -
The available-for-sale financial assets include equity investments and debt securities. Equity investments classified as available for sale are those that are neither classified as held for trading nor designated at fair value through profit or loss. Debt securities in this category are those that are intended to be held for an indefinite period of time and may be sold in response to needs for liquidity or in response to changes in the market conditions. The Group did not have these financial assets as of December 31, 2017 and 2016.
Derecognition -
A financial asset (or, where applicable a part of a financial asset or part of a group of similar financial assets) is primarily derecognized when:
| - | The rights to receive cash flows from the asset have expired. |
| - | The Group has transferred its rights to receive cash flows from the asset or has assumed an obligation to pay the received cash flows in full without material delay to a third party under a pass-through arrangement; and either (a) the Group has transferred substantially all the risks and rewards of the asset or, (b) the Group has neither transferred nor retained substantially all the risks and rewards of the asset, but has transferred control of the asset. |
When the Group has transferred its rights to receive cash flows from an asset or has entered into a pass-through arrangement, it evaluates if and to what extent, it has retained the risk and rewards of ownership. When it has neither transferred nor retained substantially all of the risks and rewards of the asset, nor transferred control of the asset, the Group continues to recognize the transferred asset to the extent of the Group´s continuing involvement. In that case, the Group also recognizes an associated liability. The transferred asset and the associated liability are measured on a basis that reflects the rights and obligations that the Group has retained.
Impairment of financial assets -
The Group assesses, at each reporting date, whether there is objective evidence that a financial asset or group of financial assets is impaired. An impairment exists if one or more events that has occurred since the initial recognition of the asset (an incurred "loss event"), has an impact on the estimated future cash flows of the financial asset or the group of financial assets that can be reliably estimated.
Evidence of impairment may include indications that the debtors or a group of debtors is experiencing significant financial difficulty, default or delinquency in interest or principal payments, the probability that they will enter bankruptcy or other financial reorganization and observable data indicating that there is a measurable decrease in the estimated future cash flows, such as changes in economic conditions that correlate with defaults.
For financial assets carried at amortized cost, the Group first assesses whether impairment exists for financial assets that are individually significant, or collectively for financial assets that are individually insignificant.
The amount of any impairment loss in the impairment identified is measured as the difference between the asset’s carrying amount and the present value of estimated future cash flows. The present value of the estimated future cash flows is discount at the financial asset’s original effective interest rate.
The carrying amount of the asset is reduced through the use of an allowance account and the loss is recognized in the consolidated statements of profit or loss. Interest income (recorded as revenue in the statements of profit or loss) continues to be accrued on the reduced carrying amount and is accrued using the interest rate used to discount the future cash flows for the purpose of measuring the impairment loss. Loans together with the associated allowance are written off when there is no realistic prospect of a future recovery and all collateral has been realized or has been transferred to the Group. If, in a subsequent year, the amount of the estimated impairment loss increases or decreases because of an event occurring after the impairment was recognized, the previously recognized impairment loss is increased or reduced by adjusting the allowance account. If a write-off is later recovered, the recovery is credited to finance costs in the consolidated statements of profit or loss.
| (ii) | Financial liabilities - |
Initial recognition and measurement -
Financial liabilities are classified, at initial recognition, as financial liabilities at fair value through profit or loss, accounts payable, financial obligations, or as derivatives designated as hedging instruments in an effective hedge, as appropriate.
All financial liabilities are recognized initially at fair value and, in the case of interest-bearing loans and borrowings and payables, net of directly attributable transaction costs.
The Group’s financial liabilities include trade and other payables, financial obligations, derivatives financial instruments and embedded derivatives.
Subsequent measurement -
The measurement of financial liabilities depends on their classification, as described below:
Financial liabilities at fair value through profit or loss -
Financial liabilities at fair value through profit or loss include financial liabilities held for trading and financial liabilities designated upon initial recognition as at fair value through profit or loss.
Financial liabilities are classified as held for trading if they are incurred for the purpose of repurchasing in the near term. This category also includes derivative financial instruments entered into by the Group that are not designated as hedging instruments in hedge relationships as defined by IAS 39. Separated embedded derivatives are also classified as held for trading unless they are designated as effective hedging instruments.
Gains or losses on liabilities held for trading are recognized in the consolidated statements of profit or loss.
Except for the embedded derivative for concentrate sales, the Group has not designated any financial liability in this category.
Loans and borrowings -
After initial recognition, interest-bearing loans and borrowing are subsequently measured at amortized cost using the effective interest rate method. Gains and losses are recognized in the consolidated statements of profit and cost when the liabilities are derecognized as well as through the amortization process.
Amortized cost is calculated taking into account any discount or premium on acquisition and fees or costs that are an integral part of the effective interest rate. Amortization under the effective interest rate method is included as financial costs in the consolidated statements of profit or loss.
Derecognition -
A financial liability is derecognized when the obligation under the liability is discharged or cancelled, or expires.
When an existing financial liability is replaced by another from the same lender on substantially different terms, or the terms of an existing liability are substantially modified, such an exchange or modification is treated as the derecognition of the original liability and the recognition of a new liability. The difference in the respective carrying amounts is recognized in the consolidated statements of profit or loss.
| (iii) | Offsetting of financial instruments - |
Financial assets and financial liabilities are offset and the net amount is reported in the consolidated statements of financial position if there is a currently enforceable legal right to offset the recognized amounts and there is an intention to settle on a net basis, to realize the assets and settle the liabilities simultaneously.