BURNT PAPA FOR ROADS.

King Country Chronicle, Volume IV, Issue 266, 8 June 1910, Page 5

BURNT PAPA FOR ROADS.

Expert's Advice. To the Editor. Sir,—Some time ago I promised Mr Thos. Williamson, of Onehunga, that I would furnish you with a brief description of my method of burning clay or papa as a substitute for road metal. I regret the delay, but a number of circumstances have contributed to same. A large portion of this County suffers from a scarcity of road metal, and for the last 15 years we have carried on papa burning," and now have some four or five miles laid down. My opinion is often asked as to how burnt papa compares with ordinary quality gravel on roads. In reply I can say that under equal conditions it is very favourable to the former. In nearly every case where papa is laid down, it is done so under the very worst conditions, i.e., on the very worst parts of back-block roads, and in desperation the settlers or local authorities are driven to try some substitute. In most cases the average quality of metal would stand no better, if as well. -For ordinary country tralfic from 12 to 15 cubic yards per chain makes a good road, and maintenance is generally lighter than on a gravelled road. The cost of burnt papa spread upon the formation complete varies according as the price of good firewood delivered on the work. Under ordinary circumstances with wood costing, say, 16s per cord delivered, it costs from 7s to Ss per* cubic yard spread and broken complete. Any good brisk wood may be used such as matai mix- ' ture of manuka, rata, maire, tawa, kawhai, titoki, matai with 10 to 20 per cent, of dry white pine or rimu. I have wood cut in 4ft lengths like prdinary"commercial wood. The best papa or clay to burn is the stiff, greasy stuff semi dry, is, not actually soaking with water. Anything of a sandy or pumicy nature is not suitable. I am conversant with the Ohura district, and such papa and clay as I have seen there should give very good results. A stiff yellow clay gives equally good results with the best papa. Our method of burning is as follows: —Select a good face of material with -as much room as possible, preferably a point which, by using the road, would be widened and straightened. Excavate as much material as can be stacked around, store a good quantity of firewood delivered close around the material. In the centre kindling is then laid down and small wood laid round on end nearly upright and gradually increasing in size so as to make a cone, leaving an eye at bottom where kindling can be ignited. This heap then is like a flue to draw out at top. Material is tfien stacked ail' around the wood heap which may he four feet in' diameter. When completely covered with material the eye is lighted and a draught draws up the fire inside. As the internal wood is consumed more is applied all around wherever the fire makes its appearance, retaining the flue-like construction. Then alternate layers of wood and papa are built on around and on top as fast as the fire appears. The centre becomes a neucleus of red-hot papa and it is imperative to have enough men, material and wood to keep the fire in, so that it does not exhaust. So the heap is kept increasing in size and is - limited only by room, if men and materials are available. In an ordinary heap from 20 to 40 per cent, will be found quite black in clinkers, balance being hard, red, bricky substance, the two binding into a firstclass road. Ordinary heap? cpntain frpm 50 tp 80 cubic yards, taut I have foirjit 140 cubip yards in a single heap upder favourable conditions. One cord of good wood will burn from five to six yards in the heap. Trusting this will be of some interest and us« to you and the many suffering settlers in the back-blocks.—l am, etc., SYDNEY A. R. MAIR, County Engineer. Rangitikei C.C., Hunterville.