Lyttelton Perlite May Soon Be Developed

Press, Volume XCVI, Issue 28414, 22 October 1957, Page 10

Lyttelton Perlite May Soon Be Developed

(From Our Own Reporter)

WELLINGTON, October 21. Lyttelton is the likely location of a large plant for the commercial development of the mineral perlite, as a result of the rapid expansion, during the past few years, in world use of what has been called “that wonderful volcanic popcorn.” An investigation by private interests has revealed large deposits of perlite in the Lyttelton area. The location is regarded as particularly favourable for development “when the increase in demand makes this economic.”

How near this point is cannot be stated by officials of the main New Zealand firm actively engaged in the industry. It is true, however, that large Canterbury construction projects, which include the new School of Engineering at “Ham” and Christchurch airport terminal building, call for a considerable quantity of perlite: and that under the present conditions all perlite supplies are imported from the North Island. The importance of the Lyttelton and other New Zealand deposits of perlite can be understood when it is realised that it is only 12 years since the commercial properties of this form of natural glass were first discovered. Perlite, described also as “pum-

ice gone wrong” is a by-product of volcanic activity. It has two most important characteristics—it is sterile and free of organic impurities: and when heated in special furnaces it “pops” into tiny bubbles which seal themselves into minute glass spheres. It can be manufactured to weigh as little as two to four pounds per cubic foot. Main Uses

Its three main commercial uses, developed over 10 years in the United States and elsewhere, are: 1. It is a first-class insulator against heat and cold, both as a loose fill and in spray and plaster forms.

2. It makes an amazingly light form of concrete, one cubic foot of which weighs only 201 b, as against 1501 b of ordinary concrete. This makes it invaluable in reducing the weight of large buildings and cutting down the amount of reinforcing steel needed. 3. In several forms, it is proving of great value in breaking up heavy soils, and in making large areas of land more porous and more receptive to the addition of fertilisers and trace elements. Some authorities say that in this respect alone it could be of greater value to New Zealand than as a building material. Investigations carried out several years ago by scientists of the Geological Survey and the Dominion Laboratory established that New Zealand had many deposits of perlite. The most readily workable at that time were found to be in the North Island thermal areas, notably about Tairua, Lake Rotoma and Ongaroto. Since then, perlite has been found in many other places. Insulation

In its expanded form it is being used as a plaster, a type of wallboard, and a form of insulation which can be sprayed directly on to steel girders to protect them from heat distortion. At present, it is manufactured in the North Island, but increasing South Island demand indicates that it is only a matter of time before a South Island factory must be opened.

Lyttelton’s claim, apart from the quality of the perlite found there, arises from the facts that it is readily accessible, that a plant established there would be right on a deep-water port, and that on the completion of the road tunnel and the strengthening of the main South Island road arteries, distribution problems would be reduced to a minimum.

“We could have a factory operating there in two years, if the demand warranted it,” said an official of the firm today. “We believe that this must come, and that it is only a matter of waiting until architects and designers become fully alive to the value of this remarkable mineral.”