Calculations
>Introduction to mining
https://pastebin.com/5uWth6eG
>Drill core sample value calculator
https://miningcatalyst.com/aueqcalculator/
>Rock value calculator
https://www.kitco.com/pop_windows/kitcorockcalc.html

>Introduction to oil & gas
https://undervaluedequity.com/oil-and-gas-companies-analysis-how-to-invest-in-energy-stocks/
https://guides.loc.gov/oil-and-gas-industry/introduction
>Natural gas unit conversion calculator
https://www.energy-sea.gov.il/English-Site/Pages/Data%20and%20Maps/calc.aspx
>Energy conversion calculators
https://www.eia.gov/energyexplained/units-and-calculators/energy-conversion-calculators.php