Commercialization of all Dore bars produced at gold operations that include Merrill-Crowe precipitation process or electrowinning are based on several conditions imposed by smelters. Some of these conditions are based on refining charges, Dore bar quality, penalties and extra credits. Also the international gold price is one of the key aspects. It is important to mentions that gold refineries usually process bars no heavier than 15 or 18 kg. It is possible to process a heavier Dore bar, but the refiner must evaluate some healthy and safety aspects of the refining process.
Some refineries are recognized by international institutions such the London Bullion Market and the refiner is accredited when have sufficient experience and the final products of the process have good quality. If the refiner is accredited, the name or mark of the refinery is synonym of acceptance by all major world gold dealers and provides assurance to the holder of its products as to quality. In this way, the refiner ensures optimum commercialization.
Regarding the refining charges, a Dore bar is usually refined at a cost ranging between U.S.$ 0.80 to 1.10 per gross ounce. In this case gross ounce is referred to the weight of Dore bar sent to the refinery. It is important to mention that the refining charge is evaluated against the quality of the bar and the cost associated to the refining process and the typical aspects covered are the services of melting, precious metals and impurities assay, refining and supply of bars to the London Bullion Market. Since the quality of the Dore bar is important, some refineries tries to process bars of certain quality such as 75% of gold. All the non-valuable elements present in the bar affect the quality of the Dore bar and the gross value is reduced. The typical non-accepted elements are iron, lead, and tellurium. The acceptance of the Doe bar may be rejected if the presence of deleterious elements is more than the common range accepted by the refining process.
Basically, the return of gold and silver present in the Dore bar is approximately 99.7% - 99.9%, and 94%-98%, respectively. The other part is the related to the losses that the refinery has to assume. In this way, the metal return is influenced by the percentage of gold and silver contained in the bar. The sale price determined in the commercialization is fixed on two business days according to the refinery indication.
The income of the gold mining company is determined by the refinery’s (outrun) weight expressed in ounces, refiner’s (outrun) gold content, metal prices, return of precious metals, refining charges, gross weight of bar received, penalties and credits. The values of the items mentioned are influenced by the refinery, refining process and production quality. Since, refineries present variable processes, they are quite variable.