BANGKOK (March 6)—Natural rubber prices are rising precipitously on the closure of Teck Bee Hang, a major Thai rubber producer with ties to the tire industry. The price of Standard Indonesian Rubber 20 today, delivered to New Orleans or Norfolk, Va., was 35½ cents per pound, about 25 percent higher than it was less than a month ago. "Consumers are assuring their pipeline for March and April," said Lou Mucciolo, president of the Rubber Trade Association of North America. Meanwhile, Thailand, Indonesia and Malaysia have agreed to open a rubber-trading joint venture in Thailand by early April, under the aegis of the International Tripartite Rubber Organization. The current price increases can only benefit that venture, Mucciolo noted.