Feldspar | Minerals Education CoalitionRelation to Mining. The top states producing feldspar are North Carolina, ia, California, Oklahoma, Idaho, Georgia and South Dakota, in descending order of estimated tonnage. Feldspar . Hard-rock mining for feldspars is done by open-pit methods, either by the mine owner or by contractors. After the feldspar ore is.best mining contractors for feldspar,Top 50 biggest mining companies | MININGApr 3, 2017 . MINING and sister company IntelligenceMine's ranking of the world's 50 largest mining companies based on market value continues to show an industry in recovery. At the end of the first quarter this year the top 50 companies had a combined worth of $842 billion. In total these companies' added $258.