Ok, I looked into it. The Peak_Truck and Min_Truck values are the number of truck loads for the ore yield to change from Initial to Peak values and from Peak to Min values. So yeah, the Initial, Peak, and Min values will all affect the rate too. So in the first mine type in mines.txt, it will take 14 truck fulls to go from initial to peak yield and it will take 50 truck fulls to go from peak to min yields.