Little-Known Deposits

Phosphate

Little-Known Deposits on N.G. Islands

ONE of the major international problems to-day is that of producing sufficient food to feed the world’s population —there is an acute shortage of food in practically every country, except the

Usa.

The two main factors governing the production of foodstuffs are labour and fertilisers. The first, since the end of World War 11, is slowly becoming avail able again, but the second, the supply of fertilisers, is still lagging far behind normal requirements.

The bulk of Australia’s phosphate fer tilisers comes from the Pacific —Nauru and Ocean Island; but the search for new and closer phosphate fields still continues.

In this connection it is worthwhile re calling that New Guinea has several un worked deposits of phosphate.

In 1941, Mr. R. C. Hutchinson, of the New Guinea Department of Agriculture, made a close survey of New Guineas potential fertiliser fields and his report, published in the “NG Agricultural Gazette” at the end of 1941, contains much interesting information.

Discovered By Germans In 1905 THE most important fertiliser con stituents are nitrogen, phosphoric acid and potash, said Mr. Hutchinson in his report. The constituents most lack ing in New Guinea soils are potash and phosphoric acid. This has been proved dinectly by chemical analysis and in directly by the remarkable results which follow the use of potassic and phosphoric fertilisers on some plantations.

Nearly all phosphoric and potassic

fertilisers used In New Guinea are im ported from Australia at a cost which makes their use uneconomical, except on the most remunerative crops. This is greatly retarding agriculture in the Ter ritory, where fertilisers are badly needed and would certainly be supplied more freely if their cost were not so high.

One way of overcoming the difficulty would be to find local sources of these constituents from which cheap supplies could be obtained. No local source of potash of commercial importance is known, but there are several sources of aosphoric acid —the two principal being the rock on certain islands and bat guano.

In 1905, the Germans first discovered rock phosphate in New Guinea. About five years later, Mole Island (a unit of the Purdy Group) was worked for phos phate under the New Guinea Protector ate, but when Nauru became the import ant source of this commodity the Purdy Islands’ deposit was practically ignored.

The Hanseatic Pacific Expedition, led by Dr. George Friederiei, investigated in 1909 a number of islands for phosphate deposits sufficiently large to be worked.

A number of hitherto geologically un known islands, and also some islands previously examined, were visited.

In 1929, the British Phosphate Commis sioners sent Mr. K. M. Fennell to New Guinea to investigate the phosphate de posits.

Two Separate Phosphate Groups IN New Guinea, there are two groups of islands on which phosphate rock exists.

One group, situated in the north western corner of the Territory, consists of Wuvulu (Maty), Aua (Durour) and Manu (Allison) Islands and the other throughout the island and the mean depth of phosphate calculated from 32 deter minations was five inches.

The phosphate was light in weight,

group, known as the Purdy Islands, is situated to the south-west of the Island of Manus.

Wuvulu Island is about five miles long and two and a half miles in breadth at its widest part. The island is surrounded by a coral reef and there is no sheltered anchorage. The phosphate deposit, which is nearly all rock, is situated in the south-west corner of the island and scattered over an area of about an acre.

It is difficult to estimate the quantity, as it is covered with dense jungle which is difficult to penetrate.

About 20 miles from Wuvulu is Aua Island, which is three miles in length and a mile in breadth at its widest part. It is surrounded by a coral reef which is about 50 yards wide in the south and from 300 to 400 yards wide in the north There is no protected anchorage. A phosphate deposit is situated about a quarter of a mile inland on the south east section of the island. It is about 1,000 yards in length, varies from 30 to 150 yards in breadth and is from 6 to 8 feet deep. It is nearly all rock, with a little alluvial which appears more like soil than phosphate. The deposit is inter mixed with broken coral-rock, sand and mud and is covered with a thick growth of ferns and creepers. The exposed pnosphate is covered with a coating of moss.

Fennell (1929) estimated the quantity at not more than 80,000 tons. In 1911, the Germans prospected the island for phos phate and their sample pits are still to be seen.

Manu Island is some 37 miles north-east of Aua and has an area of 62 acres. It is only 4 feet above sea-level and the deposit of phosphate is small. There is no protected anchorage.

The Purdy Islands THE Purdy Islands consists of five Islands—Mole, Mouse, Rat, North Bat and South Bat. Rat Island is the smallest of the group, being only about one-tenth of an acre in area. These areas were determined from a compass survey conducted by the author. This group of islands is more centrally situated with regard to the rest of the Territory than the preceding and there is a well-pro tected anchorage between North Bat and South Bat Island.

In general, the Purdy Islands are built up. Surrounding each island is a flat coral reef, part of which is just above water at low tide. The width of this reef varies from two chains at the narrowest parts on Mole and Mouse Islands to over a quarter of a mile at the widest parts on the Bat Islands.

Each island is surrounded by a coarse, white beach of coral origin, behind which there is a sand embankment rising about six feet above high-water mark. The islands are saucer-shaped, being about two feet above high-water level in the centre. In wet weather, the centres are inclined to be swampy. On all the islands there are coconuts, vines and ferns grow ing and on some islands miscellaneous shrubs and trees.

On Mole and Mouse Islands the phos phate is to be found in the low-lying centres of the islands, a few inches below the surface, as lumps of rock weighing two to 10 lb. On Mole Island, a stack of at least 400 tons of phosphate is to be found on the western end of the island; this was collected when the island was being worked by the Germans.

Low Grade Deposits ON each of the Bat Islands, the phos phate deposits extend into the sea on one side. This suggests that, in recent years, these islands have moved closer together, thus laying bare phos phatic rock which was originally in the centres of the islands.

The thickness of the phosphate layer varies greatly. In some places it is pos sible to sink a four-inch hole without striking any phosphate, while in other places it runs to a depth of three feet This irregularity of depth is found very porous and light to medium brown in colour. It was heterogeneous in com position and small white particles of shell and coral were distinctly visible to the naked eye. In general appearance the phosphate from the Purdy Islands greatly resembles samples inspected by the author from the other phosphate islands — Wuvulu, Manu and Aua.

It will be realised that the Purdy Islands’ phosphate, and probably the phos phate from the other New Guinea islands, is not of high quality. It is porous, readily absorbs water and contains a large proportion of organic matter. It is pro bably of a much later date than the de posits on Nauru and the other islands.

The rock contains a considerable quantity of lime, indicating that the phosphate is in the form of calcium phosphate.

Calculating the phosphate as tricalcium phosphate for comparison it will be seen that the New Guinea rock is considerably lower in this constituent than rock from other Pacific Islands.

Mr. S. E. Middleton, a well-known officer of the Papuan service, who has re cently been Assistant-Director in the De partment of District Services and Native Affairs under the Provisional Adminis tration, has been appointed Commissioner for Native Affairs in Western Australia.

He will be responsible for the aboriginal population-of that State. Mr. Middleton, with his wife and family, left Port Moresby in August for Perth.

Mr. and Mrs. E. Skinner, of the Central Highlands, New Guinea, with their two children, were holidaying in Sydney in August and September.