Te Kuha mine

{{#badges: CoalNewZealand|Navbar-NZcoal}}The Te Kuha mine is a proposed project located in the Buller coalfield 10 km southeast of Westport in the South Island.

Background

The Te Kuha coal deposit is located in the Buller coalfield 10 km southeast of Westport in the South Island, predominantly on an area of Buller District Council Water Conservation Reserve. An area of approximately 13 ha of the proposed mine site is on Department of Conservation stewardship land (Mt Rochfort Conservation Area and the Lower Buller Gorge Scenic Reserve). The site is currently undeveloped. Maps Photographs

In 1994, Mining Permit No 41289 for Te Kuha was acquired by Rangitira Developments Ltd (Rangitira). Rangitira is now owned by Te Kuhi Limited Partnership in which Wi Pere Investments has an 85% shareholding. Wi Pere Investments is an arm of the Wi Pere Trust, a family trust set up in 1899 by Wiremu Pere, an outstanding figure among Poverty Bay and East Cape Maori.

For some years following the acquisition of the permit, applications were made to access the land for mining and to obtain resource consents, but without success. By 2002, a mediated agreement had been reached with the Buller District Council (BDC), the West Coast Regional Council (WCRC) and the Department of Conservation (DOC) with respect to appropriate conditions of consent. However, due to outstanding land access issues and/or Rangitira’s lack of financial resources, the consents were never formally granted. An application to the BDC for access to the Westport Water Conservation Reserve (WWCR) was turned down in 2002.

In 2010, Rangitira joined with Stevenson Mining (a private company wholly owned by the Auckland-based Stevenson Group) in a joint venture to undertake further exploration of the Te Kuha resource. In 2011, Te Kuha General Partner Limited (TKGP) was incorporated, with the aim of carrying out mining under the Te Kuha permit. (80% of TKGP is owned by Stevenson and 20% by Wi Pere.) Stevenson Mining has undertaken to apply for the consents that will be required from the BDC, WCRC and DOC.

In April 2014 TKLP submitted an Application to DOC for Access to Undertake Opencast Coal Mining and Related Activities on Public Conservation Land. A separate application was made for an Easement Concession for the proposed mine access road. At that stage detailed mine planning was yet to be completed. Applications were also being advanced to the BDC and the WCRC. Amended applications were submitted in 2015 that increased the size of the mine footprint and altered the proposed route of the haul road.

The DOC Application was notified by the Department as it was deemed significant by the Minister of Conservation (Section 61C(2) of the Crown Minerals Act), pursuant to Section 49 of the Conservation Act. Submissions must be received by 09 March 2016.

Minerals Mining Permit 41289

Permit Tier: 2
Area: 884.38 ha
Operation name: Te Kuha
Granted under Act: Crown Minerals Act 1991
Duration: 25 years
Commencement date: 21 Dec 1994
Expiry date: 20 Dec 2019
Mining method: Opencast
Mineral: Coal
Permit holder: Rangitira Developments Limited
Holding: 100%
An extension to the previous permit boundary was granted on 02 Feb 2014.

Location

The permit area is described in the Access Application as being on “a ridge southwest of Mt Rochfort on an un-named range colloquially known as the Papahau Range, which lies immediately north of the Paparoa Range approximately 12km southeast of Westport and 2km north of the Buller River, at an elevation ranging from 650 m to 800 m above sea level.” The DOC Notification of Access Arrangement (AA) describes the public conservation land as being 12 ha at the very top of the planned mine site, along the Mt Te Kuha ridgeline, and lying within the Mt Rochfort Conservation Area. The area intercepts three Ecological Districts – Ngakawau (the proposed mine site), Buller (access road) and Foulwind.

Topography of the area varies from moderate to steep. The northwestern and southeastern sides of the ridge are deeply incised by numerous streams which ultimately drain to the Buller River. Yearly average rainfall at the site is 3500–4000 mm. Outcrops of bare sandstone rock are evident along the ridge crest and also on northwest-facing slopes below the ridge. Elsewhere the land Is covered with thick vegetation.

Coal resource

The coal resources on the Mining Permit area have been identified as an upper coal measure of the Brunner Coal measures that is also mined on the Denniston and Stockton mine sites. A deeper coal measure is also present and has been identified as part of the Paparoa Coal Measure.

It is anticipated that between 800,000 and 2.4 million BCM of overburden will be removed per year in order to extract 100,000–300,000 tonnes of coal per year. The anticipated mine life is 10–25 years. Preliminary tests indicate that there could be three products from the mine:

• A premium product for which the specifications will depend on the market requirements
• A lower quality (higher ash ~5–15 %) product that still might be exportable, perhaps blended with coal from larger mines
• A high ash (>15 %) product that is likely to be a thermal coal.

Te Kuha coal is described as having ash content, sulfur, rank and other coking properties that would make it valuable in both local and international markets. Additional testing and marketing would be required in order to identify a specialist market and client.<ref

Mine design and footprint

The Mine

Mining Permit 41289 covers an area of approximately 860 ha. Initially the total area of disturbance was estimated to be 85.97 ha. The updated mine footprint, submitted on 02 Oct 2015 was for 109.2 ha (approx 11% of which is on Department of Conservation land), which allowed for water management drains, an enlarged topsoil stockpile and dump area. The revised mine footprint resulted in an amended proposal to remove the tarn on the site and replace it with a new one.

The mine plan consists of two overlapping pits currently identified as the Paparoa Pit (mining up-dip south to north along the ridgeline) and the Brunner Pit (mining up-dip west to east at the northern area of the operation). It is planned to use opencast methods, including the stripping and stockpiling of soil and vegetation. The mine would operate with a pre-strip, active face and backfill operation.

The Landpro study prepared for Stevenson Mining (Oct 2015) describes the Te Kuha operation as having a number of geotechnical challenges to contend with because of the complex geology and exposure to multiple paleo-landslides (p2). The evaluation was limited by the lack of detailed geotechnical testing, but concluded that the current pit design was stable or very near stable apart from some localised hazards. Water management would be the critical aspect of controlling both the slides and general pit stability. Detailed and frequent monitoring would need to be carried out, especially in the area where it was planned to load dump material onto the crown of one of the slides.

Access road arrangements

Access to the site would be via a proposed access road which would be about 9 km long and would require significant earth works. It would provide for both light vehicles and for road trucks and trailers. At present, access is only possible on foot or by helicopter. The gazetted Scenic Reserves adjoining the Buller River were considered too “environmentally sensitive and politically difficult to be used for access purposes,” but the Water Conservation Reserves could be utilised if their “original purpose and philosophy are preserved.”

After discussions with DOC, Stevenson Mining changed the route of the proposed haulage road to ‘the upper route’ so as to avoid most public conservation land. Mitchell Partnerships reported (16 Nov 2015) that the vegetation along the upper route is similar to that in the one proposed previously. The footprint is larger than that of the previously proposed route (16.63 ha vs 14.49 ha), and although it avoids some of the high value pakihi, the total amount of rimu/hard beech forest destroyed would increase from 6.90 ha to 8.53 ha.

Approximately 1.6 ha of the proposed access road is within the Ballarat Conservation Area, but outside the mining permit. Rangitira indicated that they would be open to doing a land swap for the DOC land required for the road. This swap would involve an 8 ha freehold section of land owned by Stevenson adjoining the Lower Buller Gorge scenic reserve, which, according to the 2015 Nichol report, is of similar conservation values. Approximately 97 ha of the mine footprint and a majority of the 9 km access road lies within Westport Water Conservation Reserve (WWCR), vested within the BDC. RDL have lodged an application with the BDC for access to the WWCR.

Processing and transport

Mined coal will be trucked to a handling and washing facility, then blended and loaded onto truck or rail load out facilities. It is planned to construct a coal washing, processing, stockpiling and rail siding facility at the bottom of the hill on privately owned flat land on the Lower Buller River terrace. The preference is for transporting by rail to Lyttelton (near Christchurch) for export.

Economic effects of the Te Kuha Mining Project

As the project requires access to DOC land there is a requirement (Crown Minerals Amendment Act 2013) for an assessment of “the direct net economic and other benefits” of the proposed mining activity. An April 2014 report by Mike Copeland (Brown, Copeland & Co Ltd), prepared for Stevenson Mining stated that it was anticipated that the project would involve the recovery of about 4 million tonnes of high grade coal over a mine life of 16 years. It did not indicate who the expected purchasers of this coal would be. The Copeland report concludes that, “Expansion of mining activity offers the greatest hope of significant increases in economic activity, especially in the Buller District.”

The reason for this optimism is not entirely clear, especially given that coking coal prices continue to fall.

The Copeland report acknowledges that the Holcim cement plant at Westport (a major coal user) is closing, the Pike River and Spring Creek coal mines have closed and Bathurst’s Escarpment mine has been placed on hold because of falling coking coal prices. [In addition, production at Solid Energy’s Stockton mine has been significantly cut back, following major job losses and the placement of the company into voluntary receivership.] It appears that much of the economic benefit to the district would actually accrue from the construction (estimated to cost $40 million) and the clean-up and rehabilitation work. Royalties to the Crown are expected to be just $0.5 million per year.

Effects of the Te Kuha Project

Landscape

The site is not easily accessible and able to be viewed close-up, but, unlike most other West Coast mines, Te Kuha would be readily visible from surrounding areas. From Westport and its coastal environs it would be seen as an element of the northeast – southwest trending ranges. Photograph Aspects of the permit area and mine site are visible from high points across the mountain range and from within the Buller Gorge, especially near Cascade Corner. The DOC AA area is prominent from a landscape perspective as it sits at the very top of the ridgeline that is part of a predominantly unbroken forest-covered mountainous skyline that typifies and distinguishes the West Coast region and Buller District.

From a number of viewpoints, a skyline section of the landscape will be seen as disturbed and modified. Post-mining views will have more simplified ridgeline profiles. Broad areas such as the mined and backfilled areas that will be revegetated will have a different appearance from their surroundings for some time until the areas of revegetation mature. As viewed from the Buller Gorge, the project will have moderate to substantial effects on natural character and visual amenity value.

The Te Kuha Coal Project site has very high/pristine natural values and very high visual amenity values. The landform of the mining permit area is largely unmodified and highly legible [meaning that the processes which formed it are demonstrated]. The contribution of water to the area’s natural character is apparent in the form of a number of streams, bogs and a tarn. Indigenous vegetation cover is largely pristine. Trees up to 500 years old have been identified within the site and are part of the unique plant species distribution found in association with the existing coal measures.

Landscape effects from within the site are assessed as moderate to substantial. The sections of exposed sandstone pavement, bluffs, scarps and tors are likely to be permanently lost and/or altered by the proposed mining even after rehabilitation efforts. Twenty seven percent of the sandstone pavement within the local coal measures would be lost. (DOC, however, does not consider that this would be a notable adverse effect.)

The report points out that although coal and mineral extraction is a significant economic activity within the Buller District, tourism and outdoor recreational activities are also significant. The Te Kuha Coal Project will have moderate effects on the natural character and visual amenity on which these activities largely depend, although these will reduce with time.

Hydrogeology and aquatic ecosystems

The Golder report considers that it is not possible to avoid loss of waterways within the mine footprint. Potential impacts on watercourses and associated ecological values include:

• Loss of aquatic habitat and associated flora and fauna, especially koura
• Loss of passage for fish and other upstream moving animals
• Addition of sediment
• Contaminant runoff (eg acid mine drainage)
• Modification to downstream flows

The proposed mining activity intends to remove the headwaters of both Coal and West Creeks, which support macroinvertebrate populations. The dewatering of the mine site will modify flow regimes within Coal Creek and West Creek and result in changes to stream habitat and baseflows and a likely increase in low flow periods. Sediment may also build up, so all mine water will be cleaned through a series of settling ponds before being discharged back to the creeks. These creeks will be reinstated in the final landform in a manner as similar to pre-mining as possible. Sediment control dams will be built and maintained where necessary.

Acid mine drainage is always a potential problem with coal mining. Geochemical investigations related to leachate from rocks that will be mined at the proposed Te Kuha mine site will be used to identify acid forming and non-acid forming rocks, predict mine drainage chemistry and identify management options for waste rock where possible.

The proposed mine site is located approximately 2 km above the Westport town water supply. The mine site will need to be managed and monitored to ensure that there is no alteration in the quality or quantity of water available to the town supply. Thirteen aquatic survey sites were sampled, but mainly at a time of very low flow rates. Apart from introduced rush in the tarn, and brown trout at one of the sites, only native species were found. Riparian margins are in a natural state and the streams are considered to be of conservation value. The diversity of fish (11 species) and invertebrates is within the normal range for unmodified streams on the West Coast. Four of the fish species are threatened, and these were found on both of the sites on the DOC estate that were sampled. At the time when this report was presented (Sep 2014) a detailed mining plan was yet to be prepared. Avoidance, remediation and mitigation measures suggested by Golder Associates include:

• Briefing site personnel on the ecological values of the area
• Use of settling ponds, stormwater treatment soak pits and stormwater drains
• Develop an adaptive management plan to prevent or treat mine discharge
• Build bridges or culverts along the haul road so that fish passage is not impeded.
• Monitor water quality and biodiversity
• Translocate koura as part of a koura rescue management plan
• Site rehabilitation should include riparian plantings to restore shade and should maintain water pH similar to current levels, necessitating management of acid mine drainage.

Terrestrial fauna

Fauna values at the Te Kuha site are considered high due to the presence of At Risk/Threatened bird, lizard and invertebrate species.

Surveys carried out in 2013 indicated the presence of:

Birds
Of the 23 indigenous bird species found within the mining permit, 14 were endemic. Two of these, the spotted kiwi and the New Zealand falcon, are considered to be “threatened” and five species – the western weka, long-tailed cuckoo, rifleman, New Zealand pipit and South Island fernbird – are considered to be “At Risk”. It is possible that other endangered species – grey duck, kaka and Australasian bittern – are present within the permit area. The main effects on native birds will be habitat loss through the removal of soil and vegetation (e.g. 20 ha of fernbird habitat will be destroyed), loss of seasonal food sources, direct mortality of individuals when areas are cleared, reduced breeding success and indirect mortality due to stress as a result of enforced emigration and disturbance. The removal of habitat can result in fragmentations and loss of connectivity. Dust, vibrations, noise and the use of bright lights at night during mining operations have similar effects. Despite the effects of long term habitat loss and disturbance it is claimed that the effects on the great spotted kiwi (threatened: nationally vulnerable) will be no more than minor, and that even if their survival and reproduction is compromised there would be no adverse effects on the population as a whole. [Habitat restoration upon closure of the mine is expected to take approx 30–50 years.]

Herpetofauna
Forest gecko and speckled skink (status: declining) were observed within the mining permit area, and it appears likely that the West Coast green gecko is present.

Arboreal geckos and skinks will be killed, but it is claimed that lizards will recolonise in suitable habitat in disturbed environments and that, overall, the effect on them will not be significant.

Invertebrates
More than 80 invertebrate taxa (mainly native) were identified, and an earlier study indicates that the terrestrial invertebrate community is similar to other known habitats in the Ngakawau Ecological District. Insects identified included flies, fungus gnats and three species of weta. A possibly new species of leaf-veined slug was found at one site. A Rhytida-type land snail has been identified previously in this area.

It is considered that individual species will not be threatened because of the abundance of habitat in the surrounding area, although invertebrate communities will change over the life time of the mine. Translocation, eg of Powelliphanta spp to suitable habitat at managed sites within Te Kuha has been proposed. [Powelliphanta have not in fact been observed at Te Kuha.]

Vegetation

Characteristics Vegetation map

Most of the mining permit area is within the Ngakawau Ecological District, which is the only ecological district in New Zealand defined by the presence of extensive elevated coal measure geology with its associated landforms and plants. It includes the distinctive coal measures vegetation and exposed sandstone pavement which characterise the Stockton and Denniston plateaus, as well as large areas of pakihi, shrubland and forest and much smaller areas of tussockland, herbfield, boulderfield and wetland. Elevated coal measure habitat is recognised as being nationally and internationally unique and for having very high ecological and conservation value. Because there has been no agreement on how permanent protection of coal measure habitat on the Denniston and Stockton Plateaus will be achieved there are still large areas of unprotected coal measure ecosystems, outside Schedule 4 land, within existing mining permits.

The Te Kuha Coal Project lies within the Recommended Area for Protection (RAP) 7 in which the coal measure associations are noted as being of particular significance. Coal measures are a habitat type which is known to be declining in extent and the current mining proposal is thought to remove approximately 60 ha of the local coal measures vegetation with a smaller area, approximately 22 ha, affected by edge effects.

When the Ngakawau Ecological District was first surveyed, the Department of Conservation recommended that, should the Water Conservation Reserve ever be released from its reserve status, it should be added to the Lower Buller Gorge Scenic Reserve.

On the northwest and southeast side of the ridgeline within the permit area’s upper slopes, there is a mosaic of conifer-rich montane forest made up of mountain and silver beech, southern rata, yellow silver pine, pink pine, toatoa and mountain neinei. The northwest side of the ridge is also populated with coal measures shrubland species including manuka, mountain beech, inanga, mingimingi, kamahi, southern rate, yellow silver pine, quintinia, Epacris pauciflora, mountain flax, umbrella fern and wire rush. Large blocks of fractured sandstone are present, particularly near the ridge top, and the forest vegetation forms a mat over this broken substrate. On lower slopes within the area of the mining permit are associations of open canopy rimu/hard beech, miro, hinau/Hall’s totara, southern rata/kamahi, quintinia with kiekie and supplejack.

The 2001 survey plots from the Te Kuha mine area demonstrated a high diversity of species, including rare and threatened species and those that are taxonomically isolated or otherwise significant. One plot in particular, located within manuka – yellow silver pine shrubland within the coal deposit, was especially diverse with 51 species recorded there.

Vegetation removal
The mine plan would require the removal of approx 19 ha of manuka, 72.9 ha of mountain beech yellow silver/pink oine, 1.07 ha of rimu red/silver/hard beech and 14.87 of yellow silver pine – manuka shrubland. The amount of ‘high value’ vegetation affected by the increased footprint in the amended plan was greater than in the original.

The proposed access route would necessitate the removal of 16.63 ha of vegetation, including 8.53 ha of rimu/hard beech forest and 4.20 ha of mountain beech – yellow silver/pink pine forest.

Although vegetation will be cleared, it is claimed that this won’t have a significant effect at the population level because, due to the large amount of land currently under the DOC ownership and control, there is inherently a high level of protection of all species. The application, however, states that just ‘some’ of the vegetation types to be cleared will still be represented in other areas within the Ngakawau Ecological District. Only about 20% of the vegetation types will remain within the larger (471 ha) patch of coal measures vegetation at Te Kuha. Mining activity will remove the only example of the herbfield vegetation found at Te Kuha.

Rehabilitation

Vegetation in the Year 1 areas to be mined would be stripped and, after the logs from the mature trees removed, most of it would be mixed with soil and stockpiled for later use in the rehabilitation of mined and back-filled areas. Short vegetation (1-2 m high) of high ecological value would be salvaged and, where appropriate using a ‘direct transfer’ technique, relocated to access road batters, bunds, edges of the proposed office, workshops and infrastructure area and the ex-pit overburden from the Year 1 area.

As mining progresses, overburden will be used to backfill the pit from the previous mining. Some boulders will be salvaged and used as part of the rehabilitation process in an attempt to ensure that the post-mining landscape replicates the pre-mining landscape as far as practicable.

Weed control and biosecurity will need to be a top priority when ensuring that the rehabilitation is undertaken as soon as practicable. Active pest management will be employed on the site to ensure the integrity of the natural habitats is protected. It is anticipated that species will return to the site within 20 years of project completion (anticipated life of the mine is 10–25 years).

More recent analysis of Te Kuha coal showed it to be of higher quality than first thought. Consequently, Rangitira stated that it was looking at the possibility of establishing an activated carbon plant in Westport using Te Kuha coal.

In July 2015, Economic Development Minister Steven Joyce visited Westport and met with community and company representatives, including ones from Stevenson Group who told him that the company was proposing high-value uses for Te Kuha coal, such as carbon fibre production, and that the mine could provide 40 to 50 jobs and more employment downstream.

On 23 July 2015, Energy and Resources Minister Simon Bridges voiced support for the Te Kuha Project when addressing ‘The Minerals West Coast Forum 2015’ saying, “It’s good to see Stevenson Mining is working to develop the Te Kuha coal deposit, just north of Westport. The coal is, of course, valuable for blending with other West Coast coals for export. Stevenson is currently in the process of obtaining land access arrangements prior to applying for resource consents. And the project has the support of Buller District Council, which is the main land owner, and – I’m sure – the community.”

By December 2016 it was being stated that more than 60 jobs would be created and $20 million a year injected into the West Coast economy if the Te Kuha Project went ahead. Labour's West Coast MP Damien O'Connor said an open-cast mine in the lower Buller Gorge would be welcome if environmental impacts could be mitigated. "Those things do have to be weighed up, we don't want to destroy any rare species but they may have other areas that they can live.”

Concerns voiced by DOC reviewers

If mining at Mt Te Kuha goes ahead, then:

• Long term, the area will be ecologically different, with an altered mosaic of plant associations, lacking natural complexity and a full cover of native species for many decades.
• Weed incursion and an increase in invasive introduced species will be unavoidable, especially with the construction of an access road.
• There will be a reduction of intactness of one of the last remaining discrete areas of unmodified Brunner Coal Measure Ecosystems.
• A notable area of Brunner Coal Measure habitat will be lost, along with the fauna and flora that it supports.
• There will be a net loss of bryophyte habitat.
• Most if not all of the lizards within the construction footprint will be killed and there will be a permanent loss of lizard habitat.
• Seven notable bird species will be affected by the proposal via disturbance from construction and mining activities, habitat loss and fragmentation and in some cases possibly death.
• All aquatic habitat in the AA area will be removed/destroyed during the course of mining.
• The headwaters of all streams within the mine footprint would be lost during the course of mining leading to a direct loss of that habitat and dewatering and reduction of flow regimes in the catchments.
• The AA area will form part of an overall mine site that has the potential to increase sedimentation and affect water quality, exacerbating the effects of the access road.
• There will be clearance/destruction of exposed sandstone pavement, seepages, bluffs, scarps and tors
• It may not be possible to successfully recreate tarn and stream habitat.
• Invertebrate recolonisation of aquatic habitat following mining is problematic.
• There will be excavation and disturbance of a majority of soils within the AA area, permanently altering their structural sequence, hydrology and ecology.

Potential impacts on landscape values will be high.

Consents that are required for the project

• DOC Access Arrangement (AA) for the 12 ha of conservation land within the permit.
• Either a completed land exchange for the section of the access road within the Ballarat Conservation Area or a concession for this area.
• An AA from the BDC for access to the Westport Water Conservation Reserve for approx 97 ha of the opencast mine, and for the majority of the access road. Rangitira have lodged an application for access to the WWCR with the BDC.
• Resource consents for the entire project under the Resource Management Act 1991 (RMA). No formal applications have yet been lodged with either the BDC or the WCRC.
• Building consents for mine infrastructure and coal processing facilities.
• A Wildlife Act Authority for the disturbance/killing of wildlife.

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