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Mining on Great Barrier Island

Public meeting held on Great Barrier Island 12th April 2010.
A public meeting was held at the Great Barrier Island Sports and Social Club at Claris on Saturday 10th April 2010 between 10am and noon.
The population of the island is about 7-800 people including kids, and perhaps 300 adults were at the meeting.
The meeting was very informative, and that seems to have been agreed by a wide variety of people. Older residents and members of the old farming families seemed to support mining, along with various other individuals, some with mining experience, but the overwhelming majority of people, 85-90% of the crowd, including others with mining industry experience, were against any mining of Te Ahumata.
Don Armitage 13th April, 2010. 
 As background, read chapter 3 on Geology by Phil Moore of the book 'Great Barrier Island' .
 The Great Barrier Island Silver Bonanza











Click on image to enlarge















Source: Observer newspaper 11th Feb 1893 p13



A Rush To Great Barrier Island

                        Auckland, February 17.

There is reported to be quite a rush to Blind Bay Great Barrier Island, in consequence of recent discoveries of silver there. The tests of quartz found by Sanderson Bros., the first prospectors, have proved satisfactory and a Government Officer is surveying the claims.

Source: Otago Witness 23rd February, 1893. Page 13.




                                    [by H.O. Allom, Blind Bay.]

For the information of those among your readers who are taking an interest in the silver discovery on Great Barrier Island, I send a few lines on the nature of the country adjacent to this discovery, together with a brief description of the lode itself. In discoveries of this sort exaggerated, and often misleading accounts find their way into print, written by people who know little or nothing of what they are writing about, and who lead others to rush off to a new field only to meet with disappointment. After many years experience in Broken Hill, South Australia, and the various mining localities throughout Tasmania, I write with the feeling that I have gained some experience in these places, and, if that experience, however small, should benefit your readers, many years of privation and hardship have not been thrown away. On arrival in Blind Bay, by far the most conspicuous landmark to the new arrival, standing on the deck of a steamer, is a rugged-looking mountain, almost void of vegetation, which rises to an elevation of 1292 feet, known to the Maories as Te Ahumata, but to the settlers as the White Cliffs. The highest peak is not more than a mile from the landing as the crow flies, in a northerly direction. Its summit is broken by volcanic disturbances into many angular and castlelike forms, while bold overhanging precipices, from 50 to 100 feet high, catch the eye in several places. The mountain forms the watershed between the east and west coasts of the island, is thickly covered with masses of grey, and, in some places, pure white rocks, resembling pumice in appearance, known as trachyte, which is intermingled with blocks of white clinkstone of a slaty nature, and obsidian (volcanic glass). The soil, if one can speak of it as such, is almost white in places, sparles in the sunlight, and resembles in many respects the ash thrown out during the eruption of Tarawera, but hardened by long exposure to the weather. The vegetation is scant, chiefly stunted manuka, while here and there a small pohutukawa may be seen struggling for an existence. From the summit on a clear day a grand panoramic view of nearly the whole island is before you; to the north rugged pinnacle-capped ridges, covered with dense kauri forest, tower one above the other in bold relief, terminating in a rocky peak at an elevation of 2038 feet, known as Hirikimata, or Mount Hobson. To the east, the country falls away from your feet for about a mile, in a series of low round-topped spurs, peculiar for their bright-red colour, where numerous landslips (caused by the action of rain) expose to view the soil beneath. These spurs terminate at the Kaitoke swamp, about a mile from the mountain, and from this point to Kaitoke Beach, a distance of about one and a half miles, the country is flat and swampy. Looking towards the south-east you see most of the southern end of the island, rising in broken picturesque ridges, thickly clothed in forest of many shades of green. Turning towards the south-west the sparkling waters of Blind Bay appear beneath you with its numerous small coves and bold headlands. The mountain on this side is very broken and stony, but after descending, for about 400 feet, the spurs fall away in a fairly even grade to the coast covered with manuka scrub and clumps of native bush, while masses of white trachyte rock and huge quartz boulders rise here and there among the scrub, evidently having rolled or been thrown from the cliffs above. It is upon these spurs, and almost at the base of the cliffs, that the silver-bearing lode has been discovered.

            I believe there exists a mineral belt running along the coast, and extending inland for a distance of one or two miles. In this belt I have been shown several well-defined reefs, all carrying silver more of less, with a general strike from east to west, and dipping southerly. The reef or lode upon which the Prospectors’ claim has been pegged off is the richest so far, but is by no means the largest. The lode has been opened up in several places, and varies in width from two to six feet. The country is soft blue-and-whitish sandstone, and on the footwall, running parallel to the lode, is a seam of kaolin, about two feet wide, some of it being of a rubbly nature, but mostly very pure, and almost equal to that found in the Great Broken Hill lode. I have made several tests of this kaolin. They all show strong traces of silver. The matrix is a kindly-looking quartz, being partly decomposed in places, and showing silver in three distinct forms. Firstly, native silver, only in small quantities; secondly, chloride of silver, found very freely; and, thirdly, a form of antimonial silver known as Pyragyrite or ruby silver. When the ore is first broken out it is of a whitish creamy colour, which turns purple, and then black, when exposed to the sun, showing the presence of chloride of silver, which is found coated over the stone and in the vugs. I took samples of ore from several parts of the lode, and had no difficulty in getting a good result with the blow-pipe; in fact, the white beads were so large, that at first I could hardly believe them to be silver, but when dissolved in nitric acid, and on adding to the clear solution a few drops of hydrochloric acid, a white curd was thrown down, which turned black on exposure to the sun, it then being chloride of silver, which did away with all doubt in my mind. So far no legitimate mining has been done, only a surface scratching, and I have no doubt that when the lode is cut out at a depth of 100 feet a much richer class of ore will be found. Several samples of ore have been tested from this lead. One ton was treated by Mr. Fraser, of Auckland, yielding 94oz of silver and 6dwt of gold. Another lot of 1600lb was treated at the Thames School of Mines, and gave 41oz of silver and ½ oz of gold.

            Silver is not the only mineral found here. I have been shown a reef on Mr’ Sanderson’s property carrying a good percentage of antimony, and a little silver. Copper and iron pyrites are found everywhere associated with conglomerate and sandstone, which leads me to think that payable gold may yet be discovered in the vicinity of Blind Bay. Credit is due to the Sanderson Brothers, who, without any experience of silver-bearing ores, toiled for months, prospecting the various reefs in the neighbourhood of their own property without meeting with much encouragement, until they made this discovery. They are now very busy prospecting their claim, chiefly testing the lode in several places, and opening up new reefs.

            The Flinns, who have pegged out to the west of the prospectors, have cut what appears to be the same reef near their western boundary line. It is here 4 to 5 feet wide, and shows silver freely. Ryan, Flinn, and Werner, to the east of the prospectors, are driving to cut the lode, which they expect to meet in a day or two.

            It would be impossible to give an opinion as to the richness or extent of this discovery, so little work has been done, but the surface indications are good, and a few months fine weather is all that is wanted at present.

            The excitement has been great. Sheep, kauri gum, and firewood are things of the past. Nothing is talked of now but silver, quartz and reefs. On the hill the clink of hammer and pick is heard from morning till night, while the stacks of shapeless pegs which meet the eye at every turn makes the country difficult and almost dangerous to travel through.

Source: Auckland Weekly News 18th March 1893




23 March 2010

Media Release

All media

Environmental Defence Society astonished at proposal to allow mining on Great Barrier Island
The Environmental Defence Society says it’s very surprised that the government is proposing to allow gold
and silver mining on Conservation land on Great Barrier Island.

That proposal is very hard indeed to understand,” said EDS Chairman Gary Taylor.

“Great Barrier Island is a remote island and the area proposed to be opened to

mining is in a very difficult location.

“Access would be a real problem and there will be conflicts with existing walking

tracks and viewpoints.

The minerals identified there are gold and silver, not strategic minerals, and it’s hard

to imagine any Environment Court allowing such a development.

“One wonders where a processing plant and tailings dam could be located – possibly

on flat land near Claris?

“Mining on Great Barrier Island is a prohibited activity under Auckland City Council’s

district plan and those rules will carry forward into the new Auckland Council. That

means that an applicant is not able to even apply for resource consent.

“The only way through the Resource Management Act process would be if the mining

company introduced a private plan change. That would be very hard indeed to justify

given the natural, landscape and coastal values of the Island and the challenges of

mining in such a difficult location.

“I suspect that Aucklanders will be very upset about this. Great Barrier is the most

remote site within the City and is highly valued by island residents and non-residents

alike and by Auckland’s thousands of boaties. Already Mayor John Banks and MP

Nikki Kaye have come out against it.

“This is the tenth anniversary of the establishment of the Hauraki Gulf Marine Park.

Opening up the possibility of allowing mining in the park is a pretty poor birthday


“The government will hopefully listen to reason during the consultation process and

drop this wholly objectionable proposal. Great Barrier Island should remain protected

by Schedule 4 of the Crown Minerals Act,” Mr Taylor concluded.