NORWALK, Conn. (April 11)—R.T. Vanderbilt Co. Inc. expects to begin calling back some of its approximately 70 workers laid off within the next two weeks. The cutbacks occurred over a four-week span recently and were the result of large inventories, particularly rubber chemicals at the company´s Murray, Ky., plant, and because "business was not where we expected it to be," a spokesman for the firm said. The producer and supplier of chemical and mineral products had laid off about 50 production workers and 15 from the management side at the Murray operation. It cut another six employees at its Bethel, Conn., facility. Both plants make rubber and lube additives. "The lube additive side has been strong but rubber chemicals has been weak," the spokesman said.