Section 37N(1)(i) in The Rajasthan Minor Mineral Concession Rules, 1986
(i)a whole-time mining engineer or the person possessing IInd Class Mine Manager's Certificate of Competency issued by Director General of Mines Safety, where mining operations are carried out by deployment of heavy mining machinery for deep hole drilling, excavation, loading and transport, or where the average employment exceeds one hundred per day or in case area of mining lease/quarry licence/short term permit is 25 hectare or more.