Thursday 24 December 2015

Pike River Mine

Today's maps are of the Pike River Mine, which was developed by Pike Rivcr Coal Company (later Pike River Coal Ltd) in the 2000s and was permanently closed following an explosion on 19 November 2010 which killed 29 miners. Their bodies have never been recovered.

This overview from Google Earth shows the site of the mine top centre. The black line shows the transport route from the mine to the loading siding that was built at Ikamatua. Here, the only two shipments of coal ever produced, totalling some 42,000 tonnes, were loaded into rail wagons to be transported to Lyttelton for loading onto a ship. I believe those shipments went to India and they were undertaken in February and September 2010. The other lines on the map are mostly the railways of the lower West Coast. The mine was quite a long way from any other major mining sites that have ever been undertaken in the West Coast. It was about halfway between the major coalfields in the Grey and Inangahua areas, and as far north as coal has ever been mined in the Paparoa Ranges, which run from the Grey River to the Buller River; although there have been some small scale mines in the foothills of that range around Reefton, the Buller Gorge and Charleston.

For comparison here is the current NZTopo map of roughly the same area. In the top centre the Hawera peak at 1190 metres can be seen. The light coloured area to the south-west of the peak is where the mine is located underground. The details can be confirmed on a subsequent map, but basically from the topo map, the access road follows the Pike Stream valley and the entrance to the mine is at the stream confluence that can be seen to the east of the peak.

This is a closeup of the Hawera peak and the Pike Stream valley. The next map confirms the exact area within this in which the mine occupies. The entrance to the mine is at the end of the access road at White Knight Stream. A little way down the road are the mine buildings. Another complex of buildings, mainly the coal processing plant and bathhouse, exist at the bottom of the hill and can be seen to the lower right. The road is the mine's private access and also carried the coal slurry pipelines down to the coal processing plant. The lower complex of buildings is being removed but some of the upper buildings near the portal will be kept in place.

This is the first of my maps and shows the position of the mine and the underground tunnel. The vent stack location is not confirmed exactly in relation to underground facilities but is probably the main ventilation shaft with the fans that ventilated the mine. It is not possible to spot it on Google Earth at the present time but has been visible on other aerial coverage although I can't access any online at the moment. The western boundary of the mine is where a 45 km walking track will be extended through between the existing Pororari River track from Punakaiki and the Croesus Track from Blackball. There will be a side track of 8 km into the mine entrance area where there will be an information centre and  memorial. It should take about two years to complete the tracks. Paparoa National Park is also being extended to incorporate the mine site. 

This map shows the mine entrance and the site offices (amenities area). This is where the information centre and memorial will be located. It is not clear from the proposals if the road will be open to the public as well but it is possible that it may be.
Part of the access road along the Pike Stream valley.
At the bottom of the hill was the main entrance which consisted mainly of the coal processing plant and bathhouse facilities. This complex has now been dismantled.
Showing where the mine access road (unlabeled) comes off from Logburn Road.

This map shows that the nearest railway station in a straight line was Ahaura seen lower left on the Stillwater-Ngakawau Line. However there was not direct road access to this station because of the few bridges that cross the Grey River. Once upon a time there was a bridge at Ngahere - the one that used to be used by the Blackball Branch as a combined bridge. This survived the closing of the branch only by a few years (as a road only structure) due to it being very prone to washouts and it was eventually closed completely but there were still some remains in place until about 10 years ago. There was also the suspension bridge at Brunner that was able to be used by lighter vehicles until that was closed and then restored for pedestrians only but the trucks could not have crossed it. The nearest road bridges in each direction nowadays are at Stillwater and Ikamatua. Stillwater already loads coal for a number of other mines and could have been used, except that it is double the distance (44 km) by road compared to Ikamatua (22 km). Therefore the establishment of a completely new siding facility at Ikamatua went ahead.
Last map shows the actual loading siding at Ikamatua. A very unusual circular shaped piece of track was laid (it is not a balloon loop such as would commonly be found at major loading sites overseas - what are sometimes known as "merry go round" operations). Pike River trains would have already been heading south from Reefton to Stillwater (they may have just gone empty to Ikamatua from Lyttelton and then run around before heading back east) and would have been reversed into the siding just near Bridge 42 to load. The only real reason you would have a circular track is to fit the length of track into a particular area. There are, we suppose, many possible reasons why the track was laid out this way, probably to do with the area of land, the wish to avoid building extra bridges and perhaps avoiding a level crossing. The land it was built on is old dredge tailings as the Grey River has been extensively mined for gold over many years. The loading facility cost Pike River just over $10 million to build and was used to shift 42,000 tonnes of coal which went into two shipments from the Port of Lyttelton in 2010. As each train could carry 1500 tonnes of coal in 30 wagons, there would have been at least 25 trains needed to move that volume if they were all fully loaded with Pike River coal. Solid Energy at the time was attempting to get the size of trains increased to 45 wagons which would have made the operation through the Otira Tunnel much more hazardous and eventually this did not go ahead and trains have been capped at the 30 wagon maximum since. The Ikamatua facility was designed to allow a 30 wagon train to be loaded in one hour.

When PRC was placed into receivership the lessees attempted to cancel the leases and Solid Energy attempted to exploit this by inducing the lessees to sign up new leases with them instead but a court case went against them, finding that the lessees had no rights to cancel. SE later bought the complex from the Pike River Coal receivers. Following the liquidation of Solid Energy the complex has been dismantled.