A literal reading of "508 pounds of precious metal bearing concentrate, produced in the first 491 hours (approx,20 days) of mill operations from May 17, 2010" can be restated as "508 pounds of concentrate were produced between May 17, 2010 and June 6, 2010" If the mill did not operate continuously during those 20 days, the 20 day figure is simply a calculation of the number of days that 491 hours represents. Regardles of whether the mill operated continuously, the production of 508 pounds of concentrate in 491 hours of mill operation means an average of 1.035 pounds of concentrate was produced per mill operating hour during that first 491 hours. Any increase of extraction efficiency, volume of throughput per hour or higher value ore being processed will increase the value of the hourly production.