A discovery and rejuvenating parts of Greymouth’s CBD were the highlights of an ongoing West Coast project. Richard Silcock takes a look at what was discovered, what has been done, and what is planned.
IT MAY NOT BE a mystical El Dorado, with pathways lined with gold, nor been the scene of a wild-west movie thriller, but Greymouth, with an urban population of just under 10,000 often has bone-chilling misty days, is the home of brewer Monteith’s and has streets that are paved with coal tar.
Not an issue in itself, but the discovery of an old tar waste dump exuding dangerous toxic fumes and dust was to cause some concern for the local council and the contractors involved in the town’s redevelopment project.
According to the Grey District Council previous exploratory excavations in the area of the dump had not signalled it as an issue.
“What was discovered however was that while coal tar had been used as a road surfacing material around the late 1800s, early 1900s, when the town was a thriving centre for gold, pounamu (jade) and coal extraction, it was not deemed a health hazard as it was well below Ministry of Health acceptable toxic levels.
“But there was an unknown area that had been used as a large tar waste dumping ground,” says Mel Sutherland, the Council’s asset and engineering manager.
“The concentration in this area was so highly toxic it necessitated the implementation of additional and strict health and safety measures by the contractor, with the digger operators excavating the site required to wear protective clothing and masks and follow WorkSafe guidelines.
“Our preferred solution was to encapsulate the site in concrete,” says Mel. “However as the road level was to be lowered and with the amount of coal tar present it meant the material had to be excavated and removed. This required resource consents for both the removal of the waste and for its burial elsewhere.
“We were fortunate to be able to access a nearby landfill site for this disposal, as it had been used previously as a ‘cell’ for the disposal of other contaminated waste material.”
This redevelopment project has been the result of the Council’s economic and public surveys and consultation with a number of stakeholders, including business owners, the public and tourist operators.
This led to the formation of a project advisory group and the appointment of landscape and engineering design consultant Opus, which came up with an urban design framework to reinvigorate the central business district and ‘reconnect’ Greymouth with its past history and the nearby Grey River, which runs into the Tasman Sea immediately to the west of the town.
According to Mark Devenny, an Opus principal infrastructure design engineer, the concept plan for this upgrade was to not only provide links and reflect the surrounding natural environment but to also capture the culture, climate and heritage of this West Coast town which has its roots deeply embedded in the mining, jade, fishing and now forestry industries.
“The people of Greymouth wanted to maintain the character of the CBD and be reminded of its past through retaining and restoring parts of the town and its heritage buildings,” he says.
“They also wanted to see the streets upgraded and public green spaces created that would be inviting and accessible, that would connect with each other and the river, and at the same time provide for a range of public activities and amenities.”
Stage one of the project, which saw the creation of a town square and the repaving and landscaping of several adjacent streets, was pretty well completed at the end of last year, with the exception of a glass and steel shelter canopy over a section of the square.
The streets feature hexagonal paving, indented parking areas, street furniture and cycle racks. The square has been created at the confluence of Tainui Street, Mawhera Quay along the river front, and Mackay Street which is the town’s main street.
“The square provides a gathering place for people and is a focal point for the future redevelopment,” says Mel.
“It is aesthetically pleasing and features paved and planted areas, modern street furniture, feature lighting and landscaping.”
Significant civil earthworks were required in the form of excavating and lowering the level of the streets and upgrading or replacing some of the underground infrastructure.
Timaru based Paul Smith Earthmoving, which now has a depot in Greymouth, was tasked with this part of the work. It started with the excavation of the existing pavement and base layers of the three streets, replacing the underground stormwater services with larger capacity pipes, and then reconstructing the streets.
Its biggest challenge was lowering the street levels by 300mm, as this impacted on all the underground services and the shop frontages, but was required as a part of the design for a flatter profile and to create a more pedestrian friendly streetscape.
Basecourse and sand were used for the foundation for the ‘new’ streets with concrete and exposed aggregate paving stones laid on top. The pavers alternate in colour from dark to light and were created using a variation in the oxide mix.
“Every attempt was made to maintain normal access to shops and allow traffic movement along the streets during the course of the excavations and construction phases of the project,” says Mel.
“However, some disruption was inevitable given the streets had to be dug up and the level lowered. With the discovery of the coal tar dump, fences, plastic screens and sprinklers were used to minimise contamination and inhibit the spread of any toxic dust.”
The next stage of the project, to create a paved pedestrian link from Tainui Street to Mawhera Quay and enhance the floodwall by creating a pedestrian boulevard effect in the vicinity of the clock tower is presently under review by the Council.
Stage three would see a raised and landscaped pedestrian link to the railway station at the northern end of the town.
“When complete the CBD will be a vibrant and inviting destination, a place for people to do business, to linger, to gather and enjoy,” says Greymouth mayor, Tony Kokshoorn.
“Our CBD will celebrate the town’s natural environment, its climate, rich culture and heritage, its inspiring people and the stories they have to share of this place.”
The total cost for stage one of the project was $1.9 million and it is expected the whole comprehensive rejuvenation plan will come to fruition over time as funds become available.
This article was first published in Contractor March 2018.