I think you went to nobody's math class. The number of hours worked is not directly related to the output. The number of hours the mill runs is the important number. The plant output is 150 yards per hour. If they work a 10 hour day that's 1,500 yards per day. If they work a five day week that's 39,134 yards per month. They get approximately $1,400.00 an ounce from the refinery. So they get the following monthly numbers based on the recovery rate:
@.4 grams/yard, 486.88 ounces, $681,632.69
@.3 grams/yard, 365.16 ounces, $511,224.52
@.2 grams/yard, 243.44 ounces, $340,816.35
@.1 grams/yard, 121.72 ounces, $170,408.17
Let me head off all the other math whizzes and say these are rough numbers and don't take into account equipment failure, lack of tires, life belt drills, et al. The break even point is right around .15 grams per yard. What the MSHA numbers tell us is that they are working 50 hours per week which is good.