Multotec supplies spiral test units for both heavy minerals and coal appliions Heavy minerals pilot plants comprise 4 stages of spirals and are capable of processing up to 20 tons of dry solids per hour in the feed to the spirals The coal test units consists of double stage MX7 or SX7 spirals and are capable of processing Multotec supplies spiral test units for both heavy minerals and coal appliions Heavy minerals pilot plants comprise 4 stages of spirals and are capable of processing up to 20 tons of dry solids per hour in the feed to the spirals The coal test units consists of double stage MX7 or SX7 spirals and are capable of processing