RE: Mill Datapoints for JuniorSome smelter info:
https://www.lme.com/Sep07-article7.asp
coal $35/MWh, gas 20/MVh
https://google.brand.edgar-online.com/EFX_dll/EDGARpro.dll?FetchFilingHTML1?SessionID=qArTWgAqig4euYh&ID=5313436
Not zinc but aluminum.
1250 MV gas power plant for 1B. It's a 3.8B smelter plus value added stuff, which explains some of the capex + that power plant is oversized. The size is the same as SWN needs, alumina : aluminum ratio is 5/2.
https://www.zawya.com/story.cfm/sidGN_21042007_10119783
"Power is responsible for roughly one-fourth of a smelter's operating costs, while alumina supplies account for 45 per cent."
https://www.zawya.com/Story.cfm/sidZW20070913000105/SecIndustries/pagManufacturing
There are also coal-based opportunities in Australia, which have their own advantages and disadvantages, Knutzen said. "We're in a joint venture with a small private mining group in the north west of Australia looking at the possibility of developing a bauxite mine and alumina refinery," he noted.
So, if power is 25% of gas-smelter opex, total coal smelter opex is 18.75% higher. Smelter customers pay a fee that covers both the opex and capex. Since smelting is very capital intensive, I assume 50% of the fees customers pay are for capex.
(I saw the margins somewhere, but don't remember anymore). That is SWN smelting fees would be just 9.4% higher (this applies to both TC/RC and smelter take 85% of metal. That's because concentrate purchase was included in opex).
This was little bit feeble of course, Zn smelting is different to Al, and data used was very general. The search continues.