Types of Boundary grade KCl (%) Minimum industrial grade KCl (%) Ore grade KCl (%) Minimum recoverable thickness (m) Stone removal thickness (m) Liquid brine potassium mine 0.5 (decreased to 0.3) 1 (has been reduced to 0.5) Class a≥1 Class b ≥ 0.5 ~ 1 Class c <0.5 Solid potassium mine 2 6 Rich mine ≥12 Lean mine 6~12 Rich mine 0.2 Lean mine 0.3 0.5 Note: 1 Liquid brine potassium ore should be measured for density and associated element content. 2 solid potassium salt exposure thickness is not required. Auto Parts,Die Casting Auto Parts,Precision Cnc Machined Axle Hub,Cnc Machined Bracket Mechanical Parts Ningbo CCMS Industrial Co. Ltd , https://www.ccmcmachiningparts.com