Quarrying and Mining

Hat trick for McDonald’s Lime Quarry

By Jenny Baker

The team won a community involvement award, a safety award, and an environmental sustainability award, all in one evening. But it took years of hard work to get there.


McDonald’s Lime Oparure Quarry received three awards at the Institute of Quarrying and Aggregate & Quarry Association Combined Conference in Auckland in July.

These are the Q&M Community and Social Sustainability Award, the Winstone Aggregates Safety Award, and the Mimico Environmental Award.

McDonald’s Lime is New Zealand’s largest lime producing quarry. Situated near Waitomo Village, it occupies 67 hectares that include excavated areas, the processing plant, pastoral and forestry land, rehabilitated areas, and a limestone cave complex.

The ore body supplies around 750,000 tonnes of high purity limestone per year for commercial and agricultural use in the North Island. Holcim New Zealand owns 72 per cent and Blue Scope Steel 28 per cent of the quarry, with Holcim as manager.

The quarry, opened in 1981, has proven reserves for 70 years more production at full capacity. It employs 15 people. Quarry manager, Darcy Maddern says the team is proud of the awards: “It’s overwhelming to hear something like this ... we’re very happy, we put in a lot of work over the years to put us in this situation."

“These awards are the top acknowledgements in each category to be given within the industry. It’s great to see our commitment recognised like this,” he says.

Community involvement and safety
Maddern says the McDonald’s Lime team sees the quarry as an integral part of the local community and has a history of proactive involvement with community stakeholders. “We’re serious about corporate social responsibility. We make sure we get the message across through our words and actions that the extractive industry is not dirty, that McDonald’s Lime is a friendly, safe neighbour,” he says.

The quarry is extensively involved in cave conservation. It rehabilitated and now operates as a tourism venture the Masons Dry Cave – or Te Ana o Te Atua, Spirit Cave – which it acquired in 2000 in a damaged condition. It has also been working with the tourism industry since 1985 to optimise its blast patterns to ensure these cause no damage or nuisance vibration effects to neighbouring cave systems. In addition, it has hosted quarry open days and school group visits on a regular basis for many years.

Earlier this year it formalised an already good relationship with local iwi Ngati Maniapoto – by gaining a Memorandum of Understanding – to further enable both parties to work together in good faith for their mutual benefit.

Maddern says a strong team is a safe team. The quarry has recorded no lost time injuries since 2003, when it set itself the objective of improving its safety to the world’s best level. “We set our goal as being zero harm to all employees, contractors, and visitors by 2009.

“This means we’re aiming for more than just no lost time injuries. We’re aiming for no medical treatment, no first aid, no occupational health injuries at all,” he says.

In 2004 the company implemented a behavioural change a program to achieve this goal: “Behaviour is critical. Between 90 per cent and 95 per cent of all injuries are caused by unsafe acts, and only five to ten per cent are caused by unsafe conditions or plant,” Maddern says.

It also implemented several safety initiatives, including site safety inductions as part of contractor management, confined space entry procedures, an incident management system for reporting, and following up of incidents. “And I think the reason we’re doing so well, have such a safe workplace, is the safety initiatives are supported all the way by management commitment, high employee participation, and by interdependent teamwork,” he says.

Environmental sustainability
The quarry achieved certification to the international standard for environmental management ISO14001 in 2007. As required by the standard, the quarry sets specific environmental targets each year against which progress is measured and which are externally verified.

Maddern explains some of the environmental initiatives. He says the team carefully manages water on the property to ensure operations do not prejudice surrounding catchment water quality and quantity.

In 2005 the company installed a stone wash screen at the quarry to remove fines and clay from product. This resulted in bottom line production cost savings, better product quality, and improved environmental management synergies at both the quarry and its processing plant at nearby Otorohanga.

The screen wash water discharges through a maze of small treatment ponds that decants into a large storage pond. Much of the stormwater from the quarry also channels into this pond. Water from the storage pond is accurately monitored using a v-notch weir system, and then continually recycled.

“Every tonne of stone we wash requires two cubic metres of water. Recycling saves a lot of water – this form of water harvesting is considered both environmentally important and commercially beneficial for the quarry’s operation,” Maddern says.

In the event of significant rainfall, water discharges from the storage pond in a controlled manner via a vegetated swale before entering the Mangawhitikau River. Quarry staff monitor the quality of discharge water to ensure compliance with conditions of consent. In addition, McDonald’s recently planted native riparian plants along the river to help enhancement of the river margin in partnership with Maniapoto Maori Trust Board.

The recycled water truck wheel wash at the quarry is another recent innovation designed to prevent vehicles exiting the quarry tracking fine lime aggregate onto Oparure Road.

Maddern says stripping operations ceased five years ago. One million tonnes of overburden were stripped annually to meet the operational demands of the quarry. This required intensive rehabilitation.

After removal of the topsoil the gullies were lined with limestone cap rock. This enables stormwater runoff to percolate through the clean rock before reaching underground waterway systems. Siltstone was then compacted over the cap rock to provide a solid bed for the volcanic ash to follow.

At strategic intervals, cap rock sumps ensure water runoff reaches its normal discharge stream so underground water tributaries in the system are not affected. Maddern says 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”.

Over the past 27 years the team has rehabilitated large areas of the quarry site for agricultural purposes to a condition better than that present prior to quarrying. Rehabilitation is designed with future land use in mind and with community involvement. In addition, the company acknowledges it is in an energy intensive business. It recognises the need to reduce global greenhouse gas emissions and energy consumption while fostering economic and social development.

“We’ve adopted a ‘measure to manage’ approach to carbon dioxide and now measure emissions per tonne of quarry product as a key performance indicator. We also benchmark these against quarry international best practices.”

“These initiatives not only reduce the environmental impact of the quarry’s operations, they also enhance the quality of its surrounding environment and its reputation within the local community. It has also increased the sustainability of our business in terms of overall productivity, energy efficiency, and cost savings,” Maddern says.