or comme sous-produit

OBS: Localement, apparaissent : or, pyrite, arsénopyrite et cinabre. L'or est récupéré comme sous-produit.
OBS: [...] on peut distinguer les gisements dont l'or est le produit principal, comme au Rand, ceux où l'or n'est qu'un sous-produit (volcano-sédimentaires et porphyres).

CONT: Byproduct gold from volcanogenic massive sulphide deposits, nickel-copper deposits, porphyry copper-molybdenum deposits and vein copper deposits accounts for approximately one-third of Canadian resources. The remainder occurs in gold-only deposits ...
CONT: It is important to note that precious metals are also produced from some... deposits, indeed in some Canadian examples they are the prime product. Thus both Besshi and Kuroko types [of deposit] may produce silver and gold whilst the Cyprus type may have by-product gold.