Bucket Elevator As Dewatering Plant

Northern Advocate, 17 March 1939, Page 8

Bucket Elevator As Dewatering Plant

Where r centrifugal and vacuum pumping has failed because of mineral content in the water, an ingenious, endless chain with bucket scoops is succeeding in dewatering diatomaceous earth workings on Kamo Flat. Tadpoles, frogs, and fresh-water crabs were a lesser problem when the ordinary methods of pumping were employed.

The property is owned by the Crawford Mineral and Transport Co., and the deposit of diatomaceous earth, found from about four feet under the surface, and continuing to a depth of between 70 and 80 feet, extends for several acres.

Diatomaceous earth is used principally for insulating purposes, being compressed into bricks which are impervious to heat, cold and sound. Pool 20 Feet Deep.

Commercial possibilities are limited to a restricted area owing to the great bulk of the material and the high cost of transport. When burnt, 10 cubic

yards of the powdery earth make one ton weight of bricks. During the rainy season large holes formed by previous working of the deposits became filled to a depth of about 20 feet with water.

Mineral gas present in the water had a similar effect to an air leak in the suction pipe of pumps, and the company was faced with abandonment of the workings unless the difficulty could be overcome.

Mr S. C. Crawford, of Whangarei, the principal of the firm, together with the Auckland Gas Company, designed the apparatus which is now in use. Weighing about four tons, it was erected by three men. It operates on the elevator principle, with an endless chain to which are attached bars and buckets.

The bars bolted between the chain and the buckets are run in steel guides both underneath and above the elevator ladder, which keeps the buckets in position and tends to smoother running so as to ensure as much water as possible being cax’ried in each bucket.

A Young River.

The buckets travel at 95ft. a minute, and since the plant was erected, nearly 6000 gallons of water an hour have been lifted.

The buckets empty into a chute from which the water runs like a young and rapid river.

All told, about 150,000 gallons have to be dealt with, and with the present rate of progress the job should be completed within about five days. The buckets were fabricated at the Auckland Gas Company’s works.. Mr Sydney Western, foreman of the Devonport Gas Works, assembled the apparatus, and together with his assistant, Mr Ivan Sterling, previously of Whangarei, is in charge of dewatering operations. The plant, which is quite unique, is to be kept on the property for further work of this nature.