LIME DEPOSITS

Otago Daily Times, Issue 19066, 11 January 1924, Page 14

LIME DEPOSITS

The TaJne of lime in connection with agricultural operates is too well known to require any emphasis at this stage. Practically every farmer knows that the fertility of the soil is governed by the amount of carbonate of lime present, and experience has shown that remarkably good results have been v secured as a result of the judicious us© of this commodity. In places where the soil has shown a tendency towards sourness a marvellous change has been effected through the application of lime, which also acts on other ingredients in the ground so that Elant foods which would otherwise not e available are liberated. The fertility of the land on the Tokomairiro Plain today is largely due to the use of lime, and in other districts its value has been proved beyond the shadow of a doubt. The importance of encouraging the use of lime on farm lands was recognised by the Government many years ago, and special facilities were afforded for its conveyance by the railway so as to bring it within the reach of all.

The pioneer in the lime burning industry was Mr Jas. M’Donald, whose first works were situated at Sandymount, on the Otago Peninsula, where they are still in existence. In company with MiDriver, Mr McDonald started to exploit the deposits at Milbum about 1882, but j.ust as he was getting into his stride he met with financial difficulties, and the Milburn Lime and Cement Company was formed in 1888 to Iteke over the works from the official assignee. Mr M'Donald then started lime works at Totara, in North Otago, where operations have been successfully carried on ever eince. Mr M'Donald had two kilns at Milburn, and turned out about 10 tons of lime per day, but the company gradually increased the output, and is now capable of turning out 140 tons of burnt lime and 100 tons of carbonate of lime per day.

When the company was formed the capital was £30,000, in shares of £1 each, but owing to the expansion of operations it was found necessary- at the end of 1897 to increase the capital to £75,000, and in September, 1918, it was further increased to £150,000. The original directors were Messrs J. W. Brindley, Henry North, and John White. Mr Frank Oakden held the position of general manager for many years, and on his retirement Mr J. H. Stewart |(the present manager) was appointed to take his place.

The company’s property comprises 1300 or 1400 acres of freehold, not all of which, however, carries deposits of lime. Only a very small portion has yet been worked, and it is a reasonable assumption that many years will elapse before the supplies are exhausted.

Horses were used for haulage purposes in the early days of the company’s existence, but later on these were replaced by a steam locomotive, a railway being laid down to connect with the main south line. Winches driven by electric power are used to haul coal up the hill to the works, but the bulk of the plant is operated by electricity.

Within the last few months the company has put in a mechanical drier, and has installed screens with the object of giving farmers a finer product. During the current year it expects to be in a position to supply anv kind of lime required and also ground limestone. Probably nowhere else have the beneficial effects of the use cf lime been more apparent than on the plain lying immediately below the Milbum works. Years ago the Tokomairiro Plain was practically covered with sorrell, hut through the use of lime the land was improved from a value of about 50s per acre into a highly productive area probably worth as many pounds per acre. The quarry face averages about 100 ft in height, and the amount of overburden is not very considerable. The stripping is sent down to the quarry floor, where it is loaded on to drays by an electric digger, the capacity of which is eight loads in five minutes. * The quarry- floor is well laid out with railways, and when the trucks of. stone are loaded they are conveyed to the crusher 400 yards away, by a petrol engine. In order to provide for the insertion of explosives the stone is bored by a compressed air drill, pie crusher, which is driven by electricity, has a capacity of 60 tons of stone per fcpur. After being crushed the stone is elevated a distanse of 65ft, and then goes into a rotary sorting screen, which .is divided into three sections. The first section is punched with half-inch holes, through which all the fine stuff and “peas” pass. The second section takes all the nuts, or pieces that can pass through a- sieve, punched with holes 2in by 2-1-in, these eventually going to the rotary kiln to be burnt. The oversize pieces of stone are loaded into trucks and conveyed to the old underground kilns, where they are dried prior to going through the carbonate mill. Tht “rotary kiln, which was made at Port Chalmers, is 110 ft long and has a diameter of Bft. It makes one revolution in 90sec, and is driven by a 30 h.p. electric motor. The lime occupies from three to five hours in passing through the kiln, and when it emerges it is red hot, having the appearance of intenselyheated metal. The lime enters the kiln at the rate of six tons per hour for 24 hours every day except Sunday, and it comes out kt the rate of a little over three tons per hour, the difference being accounted for by the amount of carbon dioxide and moisture drawn off during the burning

process. There are at present more than 50 men employed at the works, and a good deal has been done to provide for their requirements. They have comfortable huts as sleeping quarters, and get their meals in the company's dining room. There is a good water supply, a reservoir with a capacity of 128,000 gallons having been constructed. It may be mentioned that the company also owns lime works at Makareao, near Dunback. These works were started by the Government about 23 years ago, with the object of providing cheap lime for the farmers, but the venture was not a success, and the property was taken over by Mr Jas. Gibson, wlio carried on for some years, selling out to the Milburn Co. about 14 years ago.

The record of the activities of the compazny would not be complete without a reference to the cement works at Pelichet Bay. Mr M‘Don aid was also the pioneer in' this industry’, which was originally carried on at Fairfield. About a y’ear after the Milburn company took over the property’, however, the works were shifted to Pelichet Bay. The erection of the present works vvas commenced about 1889 or 1890, and operations have been earned on there ever since.

THE WORKS AT MILBURN.

property comprises very line deposits of low grade phosphate. £n the early stages of the company’s career everything went well, but in recent years the phosphate produced at Clarendon has been displaced to a large extent by the article imported from Nauru. The company hopes, however, that if. will regain its lost trade in the near future. The product of the Clarendon works is phosphate of lime, which is more readily assimilated than the Nauru phosphate, and it was largely on the former that the New Zealand I)rug Company built up its extensive trade in basic phosphate.