My suggestion is to work from 1.67 (which was initial guidence) and just move it up or down based on assumptions. Example, lower output would increase AISC, higher output would lower it. Cost of sulfuric acid going up/down, power grid usage (which has gone up to 85% more than expected), currency etc.
TGS Price at posting:
4.3¢ Sentiment: Hold Disclosure: Held