A CENTENNIAL SURVEY

Press, Volume LXXXVI, Issue 26212, 8 September 1950, Page 6

A CENTENNIAL SURVEY

CANTF.RBURY’S MINERALS

fSpeetaUv written for -Tht Press" by B. W. COLLINS) 1

This is the first ot two articles in which Mr Collins surveys the This is me nr« mineral resources of Canterbury.

“Modem civilisation ia dependent on the use of large quantities of three natural resources: metals and nun erals for machines; fuel for power and heat’ and water for power, irrigation, industry, and the home. These resources come from the earth, a ” d most efficient discovery and development require a knowledge of With these words the director of the United States Geological Survey beßan his annual report for 1948. He might have added a fourth class of important natural resources, in the P ro<,uct , l< ’" b ? 7 which geology can play a valuable part—minerals and rocks f ° r Pje building, manufacturing, and fanning industries, including here grovel »nd sand, clays and limestone, which are just as much mineral products as gold, iron or coal. .. This centennial year provides a suitable opportunity for a survey of the mineral resources of Canterbury. ft may surprise many to find that this province, generally considered almost wholly lacking in economic minerals, has in fact a large mining industry, with abundant opportunities for great expansion. v In the early days of white settlement in Canterbury, especially after the important gold discoveries in Otago and on the West Coast, high hopes were entertained that valuable deposits of minerals would be found in this province. It was no doubt partly for this reason that the provincial government of the infant colony appointed Julius Haast (later Sir Julius von Haast) official geologist in 1861. When he failed to locate the expected rich lodes of metallic minerals von Haast was criticised by many, and eventually his appointment was terminated. Haast, however, both while he was Provincial Geologist and later as Professor of Geology at Canterbury College and Curator of the Canterbury Museum, did valuable work in laying the foundations of our knowledge of the geology of the province and made many notable contributions to the science. He established a world reputation as a geologist, and his work greatly assisted in the development and exploitation of the gold and coal on the West Coast. It was not his fault that Canterbury east of the Alps proved so disappointing to his contemporaries in its supply of mineral wealth.

Gold-mining Attempts Several abortive attempts were nevertheless made to develop reported gold-bearing lodes—near Gebbie’s Pass at the head of Lyttelton Harbour, in the Malvern Hills, at Kakahu near Geraldine, at Myers Pass at the head of the Waihao river, and the Westland reefs in the Upper Wilberforce river near Brownings Pass. Although some gold was found at most of these localities, it was in such small quantities that its extraction was not a payable proposition. In the case of the Westland reefs, the question of access was perhaps the main factor operating against their successful development, as some specimens were shovzn by assay to carry as much as 10 ounces of gold a ton. These reefs are, however, situated at altitudes of up to more than 5000 feet near the Main Divide at the head of the Wilberforce river, one of the main branches of the Rakaia.

Various other metallic minerals have been prospected for. and some have been found in small quantities—such as silver, copper, manganese, and iron. Canterbury even had its “diamond” rush in the eighties, to Taylor stream, in the Mount Somers district, north of Staveley. The “diamonds” were, however, unfortunately, merely quartz crystals weathered out of the rhyolite rock of the locality. The fact remains, as pointed out long ago by von Haast, that the rocks of which the m?in mountain axis of Canterbury are composed are unlikely to contain important mineral lodes. Similarly, the rocks of the foothills and plains, most of which have been formed largely from the breakdown of the older rocks of the mountains, are also unlikely to be sources of valuable metalliferous minerals. Even as far as non-metallic minerals were concerned, the early settlers were doomed to disappointment. The Malvern Hills area was first thought to be hkely to develop into a rich coal field. Though some deposits of very high Quality coal were indeed found further investigations showed that these were merely locally altered patches of a seam of lignite, which itself was not t hic k or very ex tens ve. high hopes, preserved in such names as Coalgate and Sheffield, were not long maintained. Nevertheless coalmining in a small way has been carried on m this and other districts of the province for many years; and Canterbury s coalmines have many years °r ufe yet at the present rate of output A mine in the Mount Somers district is said to be the third oldest in ?o e o « havin S been worked since 1866 Only two mines in Otago were worked earlier.

At present, besides the Malvern Hills

and Mount Somers areas, coal is also produced near Albury in South Can terbury. In the past, mines have also been opened up near Waimate and at Avoca on the Midland railway line and thin seams of lignite are known in a few other parts of the province Nevertheless, it must be conceded that Canterbury is poorly endowed with coal, and will always have to impor* the greater part of its supplies irom other parts of the country. The total production of coal in Canterbury during 1948 was only 31,330 tons, compared with 585,489 tons Irom Otago and Southland, and more than a mu. lion tons each from the rest of the South Island (Nelson and the West Coast) and the North Island respectively—giving a New- Zealand total of 2,775.886 tons. Canterbury’s percentage of the New Zealand output is the-e. tore only a fraction over 1 per cent Small Coalmines During 1948 13 coalmines were being worked in Canterbury, the lara. cst employing only 17 men. Tlie total number of men employed, both above and below ground, was 72. In New Zealand as a whole there were 18S mines, employing 5582 men, the largW being at Stockton, near Westport, with 333 men. It is interesting to note that in spite of the recent great expansion of opencast mining, all Canterbury coalmines are underground working! This fact is a reflection on the m<xie of occurrence of coal in the provincein relatively thin seams, generally not lying flat but dipping at an angle, and in many places broken by faults Extensive areas of flat-lying coal with a low overburden coal ratio, suitable for opencasting, are unknown. It is quite understandable, therefore, that Canterbury has long been coni sidered almost devoid of mineral resources. The products of the soil have quite overshadowed those of the ground, and the province’s reputation is largely based on its agricultural and pastoral products and its manufacturing industries. But this picture is by no means the true one. Coal and gold are not the only minerals. Other and no less important materials are produced from the ground, and Canterbury is very fortunately situated in many respect! Little need be said about the queition of water supplies, other than to point out that Canterbury’s potential reserves of both surface and ground water are probably greater than those of any other province in New Zealand The future of Christchurch as an industrial and residential centre will rest largely on the capacity of tha ground to provide adequate water supplies. Ground water is already being utilised in a few places also for farm Irrigation, and this use could be vastly increased. Thermal and mineral watem also are found, and the spa at Hanmer Springs could be developed into a first-class tourist attraction. Of the solid mineral products, perhaps limestone sand and clay are ths most important in Canterbury. In the last few years the Geological Survey has devoted some time to the investigation of these materials in various parts of the province. Besides these however, Canterbury has important and useful deposits of first-quality building and ornamental stone, and unlimited amounts of material suitable for road metal, concrete aggregate and building blocks and plasters of various kinds. In New Zealand as a whole during the last few years the production of non-metallie minerals other than coal has far exceeded in value that of metallic minerals- and despite a decrease of £200,000 in the value of gold produced in the country during 1948 as compared with 1947 the production of non-metallic min: erals has increased in value to such an extent that the value of the total mineral production has remained practically constant. The figures for 1948; extracted from last year’s Mines statement, are as follows:

Value r . (*N.Z.) r olG •• •• <m .. 895.173 ~ther metals Total metals .. .. 972,501 ?j«y 15 Limestone (for agriculture) 473,703 Limestone, marl, etc. (for cement) 88,454 Sand, gravel, etc. (for roads «nd tailast) 608,10 Sand, etc. (for building aggreSate) 141,504 Dimension stone (for building) 34.380 Serpentine ie.447 Silica sand 44,774 Othqr non-metals .. 52.303 Total non-metals .. .. 1,487,692 In round figures, therefore. New Zealand’s annual coal production Is worth £5,000,000, metal production £1,000,000 and the production of nonmetallic minerals other than coal £1,500,000. It is to this last category that Canterbury contributes a not inconsiderable portion—and could well contribute more. (To be concluded.)