jiggingtechnologyprocessimprovementcoalwashing
In year 1820, German professor Dr. Hartz developed ROM Jig to fixed screen piston jig, and it was used for minrral processing by pulsating water flow, in 1840 it was used for coal washing. In year 1848, French professor Dr. Berard developed piston Jig for coal washing which can continuously work, it obtained British patent in year 1851, and was promoted to France, Belgium, Germany, USA and other countries.