Q3 produced 50 oz of gold, with 2279 hrs (some of which was for repairs as opposed to mining). Q4 presumably reduced the time on repairs (i.e., a higher percentage of total hours likely were devoted to mining in Q4 than in Q3) and tripled (i.e., 6674/2279) the number of total hours. And I suppose it is possible that tweaking the process increased the extraction rate.
So production = 50 oz x 3 x R x P, where:
R = rate of extraction in Q4 versus Q3, and
P = percentage of hours mining in Q4 versus Q3.
When does the train reach Chicago?
Go $PCFG