When quarrying and tourism meet

When it comes to community relations, the McDonald’s Lime Oparure quarry in the Waikato has set a high standard for others to follow.

McDonald’s Lime’s Oparure Quarry operates five kilometres south of Waitomo Village and seven kilometres west of Te Kuiti. It is the largest lime-producing quarry in New Zealand, supplying over 750,000 tonnes of high quality limestone each year for commercial and agricultural use throughout the North Island.

The quarry occupies an area of 67 hectares which includes excavated areas, the processing plant, pastoral and forestry land, rehabilitated areas and a limestone cave complex that includes two of the country’s tourism icons – the Waitomo Caves, Lost World and McDonald’s own Mason’s Dry Cave.

Through projects aimed at corporate and social responsibility, the quarry has gone way beyond its consent compliance and consequently become an important member of the Oparure, Waitomo and King Country community.

“Voluntary initiatives focused on sustainable development have proved that what is good for the environment is also good for business,” says quarry manager Darcy Maddern.

“McDonalds Lime views itself as an integral part of the local community and has been extensively involved with cave conservation and other initiatives that have demonstrated the company’s strong commitment to corporate social responsibility.”

This has included working with local tourist industry to optimise blast patterns to prevent effects on cave infrastructure, he says. McDonald’s Lime also signed a memorandum of understanding with the local iwi, Ngati Maniapoto, and has regular open days at the quarry for school students.

The quarry has regularly held open days which have become a highlight on the Community’s calendar and feature tour of operations, a blasting demonstration and a barbecue.

“Over 200 visitors came to the reasonably remote quarry location during the last open day. Visitors included neighbours, customers, key suppliers, iwi, and regulatory bodies,” Maddern says.

The quarry also hosts secondary school visits, where geology and chemistry students get the chance to view first hand raw material resources extraction methods and final uses of these materials.

“The purpose of encouraging community to visit the site in this manner is to help inform stakeholders that the quarry industry is not a dirty one and that Oparure Quarry in particular is a well-managed and professional operation.”

Another valued neighbour is the local tourism industry. The Lost World is just 1.3 kilometres due south, says Maddern, and the Waitomo Caves five kilometers north. The quarry sits on the same fault in the local karst and cave areas.

“McDonald’s Lime has undertaken a lot of work (in combination with Prime Explosives) in optimising blast patterns to ensure the minimum amount of explosives are consumed to achieve optimal stone size and minimise ground vibration per tonne of rock.”

 Recent blasting has achieved a powder factor of 0.28 kg/m3 (ie. using 0.11kg of explosive per tonne of rock). To date, the company has been successful in avoiding damage or nuisance vibration effects to neighbouring cave systems.

The company became extensively involved with a cave conservation project that later turned into a tourism operation in Masons Dry Cave. Masons Dry Cave (also known as Spirit Cave or TeAna o Te Atua).

The cave, located on land North East of the quarry, had been badly damaged over the years and was bought by McDonald's Lime in 2000. Since then the company has worked with local commercial cave operator ‘Spellbound’ to clean up and rehabilitate the cave to its natural state. It now operates as a popular tourist attraction with over 2000 visitors a year.

The cave is part of the Mangawhitikau system and now features an all weather access, full wheel chair accessibility, cave lighting and a complete fossilised moa skeleton.

“In 2005 the cave hosted two BBC film crews led by Sir David Attenborough who were amazed by the dense and magnificent display of glowworms in our glow worm cave,” says Maddern.

Onsite, water for the quarry has been carefully managed and improved to ensure surrounding catchment water quality and quantity is maintained and enhanced. Improvements in stone washing, truck wheel washing, water harvesting and treatment processes have not only reduced the environmental impact of quarry operations, they have also increased the overall productivity and energy efficiency of the quarry, says Maddern. Much of the stormwater from the quarry is recovered and put into the storage pond for use.

“For every tonne of stone requiring washing, two cubic metres of water is needed. By recycling the water in this manner, a significant amount of water is saved from the quarry operations. This form of water harvesting is considered both environmentally important and commercially beneficial for the quarry’s operation,” says Maddern.

The truck wheel wash at the quarry is another recent innovation which was designed to prevent the quarry vehicles exiting the quarry tracking fine lime aggregate onto Oparure Road. The truck wash at the quarry is also very effective and represents a best practice approach given that it also recycles water used.

Large areas of the 67 hectare site have been rehabilitated for agricultural purposes and are now in a condition better than that present prior to quarrying.

Maddern says Oparure Quarry’s aim is to rehabilitate land to a better condition than it was found in. Up to one million tonnes of overburden has been stripped annually to meet the operational demands of the quarry, which has presented challenges to the quarry operations.

“After removal of the topsoil the gullies are lined with limestone cap rock which enables natural storm-water runoff to effectively percolate through the clean rock before reaching underground waterway systems. Siltstone is compacted over the cap rock to provide a solid bed for the volcanic ash to follow. At strategic intervals, cap rock sumps ensure all water runoff reaches its normal discharge stream so underground water tributaries within the karst system are not affected. This rehabilitation programme has improved the quality of the surrounding waterways, ensuring an effective filtering system for water before it discharges into creeks and streams.”

Prior to rehabilitation, gullies were previously being farmed with difficulty due to steep slopes and limestone bluffs where stock would often be lost. The restoration plan was to return these areas to pasture but with a contour that would not appear out of place and would be conducive to the type of farming being undertaken.

“Involving the farmer at an early stage of the rehabilitation assisted McDonald’s Lime in identifying areas to be used for grazing. Rolling terraces were designed to support the intensive farming style. Special grass seed types and a rigorous soil analysis programme were selected to enhance dairy grazing. Quarry management controlled the grazing movements, fertiliser and lime applications for 12 months before handing the land over to the farmer for full productive use.”

Maddern says that, to date, these sustainability-focused initiatives have not only provided significant benefits to the environment, but have also contributed to company’s business success. “McDonald’s Lime plans to continue these environmental initiatives and the involvement of the community well into the future.”

• Based on a presentation at the 2008 Quarry Conference by Oparure quarry manager Darcy Madden and Holcim environmental manager Greg Slaughter.