When concentrates of the less common ores must be sold it is necessary to make special contracts with the comparatively few buyers who are in the market for such products. These 1955 numbers can be indexed by multiplying by 8-10X t obtain 2016 values. GOLD and SILVER Marketing
Metal Payment. Gold: Deduct 0.02 Troy ounces per short dry ton sdt and pay for 95% of remaining gold at London final quotation less $5.00 per ounce. Silver: Deduce 1.0 Troy ounces per sdt and pay for 95% of remaining silver at Comex 1st position quotation less 25¢ per Troy ounce.
The dried concentrate contains approximately 20 -30 percent copper by mass 30 per cent iron 30 per cent sulphur with the remainder including small amounts of gold silver and unwanted elements such as arsenic and mercury. Exported copper concentrates are transported by sea as a bulk commodity either in drums or packages or as loose powder.
There are many other penalty elements and if some elements are high enough the concentrate may not even be saleable. If we assume a gross metal value per tonne of concentrate of USD1200 the net amount payable to the seller could be of the order of USD800 after all charges and penalties. Thus only 67% of the value of the metal in concentrate
I show how I hand pan my concentrates and recover the gold from the black sands and heavies from my dredge. Its a good Idea to super concentrate your materia
Gold-copper mining companies would only use a Kyrgyz plant if the government levied a tax of at least 15 percent on the gross value of concentrate. If companies could not avoid this tax by processing their concentrate domestically they would probably carry one of the highest tax burdens among mineral producing countries.
Copper concentrates come in two “flavours” – Clean and Complex. Clean copper concentrates have more than 20% copper and possibly gold and silver and low levels of the deleterious elements As As Bi Cd Cl F Pb Hg U and Zn. In addition asbestos referred to as fibre is present in a small number of … Continue reading complex copper concentrates
concentrate having up to 25 times the penalty limit of 0.02% Bi in concentrate. The approximate compositions of these select concentrates are listed in Table 6. Table 6 - Chemical Analysis of High Bismuth Bearing Concentrates Concentrate Bi % Cu % Fe % Cu:Fe Mid-Grade Cu 0.3 27 22 1.2 High-Grade Cu 0.5 35 17 2