The rest of the reserves are not recovered in the mining process. From the December 21, 2012 press release " Metal recoveries to the copper concentrate containing at least 28% copper content are expected to be 86.6% for copper, 73.0% for gold and 48.3% for silver. The molybdenum recovery to the molybdenum concentrate (+50% Mo) is estimated to be 58.8%" For example 4.875/5.6 billion pounds of copper= 87% recovery for cu. One of the recommendations from the FS was to look for improvements in metal recovery rates. The losses are significant.