SUBSTITUTE FOR METAL

New Zealand Herald, Volume LXXI, Issue 21742, 6 March 1934, Page 11

SUBSTITUTE FOR METAL

SOIL-BAKING ROAD PLANT USE IN CLAY COUNTRY EXPERIMENT IN QUEENSLAND The operation of a new system of road construction in Queensland was outlined yesterday by the Hon. H. A. Bruce, Minister of Works in the Queensland Labour Government, who arrived at Auckland by the Aorangi. He is accompanied by his wife and they intend to spend a month's holiday in New Zealand. In some of the sheep country in New South Wales and Queensland, Mr. Bruce said, there were largo areas in which there was no metal available for road making. The soil consisted of dense, heavy clays and, although roads ivore necesi3arj\ the cost of transporting large quantities of metal over long distances had always presented difficulties of finance. However, these difficulties had been overcome by the use of a soil-burning plant, invented recently by Mr. L. H. It. Irvine, an Australian road engineer. The basic principles of the system were similar to those: employed in brick making. Either a stationary or a movable plant was used and the natural soil was subjected to a high degree of heat, which baked it, made it impervious to moisture and rendered it the equivalent olf C grade metal. After the baking of the soil the road was formed and rolled and a surface resulted which to date had stood up to all tests most satisfactorily. "The Queensland Government has obtained rights for the use of this system throughout the State," Mr. Bruce said, "and I understand the New South Wales Government is also interested. It is a system which can prevent clay -reads from becoming a motorists' terror and as such :is most valuable. Movable plants are generally used in actual road construction." in other parte of the back country, Mr. Bruce continued, tarred metal roads were the rule, while bitumen surfaces were provided near the more populated areas. Adjacent to the cities and on low-lying areas subject to ilood, the concrete-penetration system was used.

Such a wide area came within the scope of the Main Roads Commission, controlled by Mr. Bruce's department, that surveying difficulties frequently arose. Large areas, particularly in the far north, were covered with dense scrub, providing surveyors with an almost superhuman task in their efforts to plan roads. However, in recent years extensive aerial surveys had been carried out by the Government with the result that roads could be laid out by air in three months that would take surveyors working in the ordinary way at least two yeairs. , Mr. Bruce mentioned that the production of power alcohol in Queensland was also supervised by his department. About 500,000 gallons were produced annually and that amount could be increased.