National Gypsum (Canada) Ltd., Nova Scotia, operator of the world's largest open-pit gypsum mine, ordered 132 newly-designed automatic discharge aggregate hopper cars from Johnstown America Corp. NG will use the cars to haul gypsum rock from its mine at Milford Station, 32 miles north of Halifax, to the Port of Halifax. There, the rock is unloaded and exported by ship to customers in the U.S. and Canada, Delivery will be completed this spring. JA designed and built the cars to meet ...