Get (almost) to the bottom of it

These budding geologists visited from Tauranga.

Martha Mine recorded an operating noise level of 124 decibels on Sunday 17 January. No operations were stopped, no exceedences logged, and no regulators were informed despite the permitted maximum noise level being 50dBA at the residential boundary.

The fact that it was a child screaming at this volume was also not seen as a cause for concern by the crowd of over 5,000. It was all part of Martha Mine Open Day, held by Newmont Waihi Gold in partnership with Vision Waihi Trust, to 'demystify' the mining process and raise money for the community.

The noise level? - a 'yell-o-meter' operated by the Environmental Department, just one of many child-friendly activities on site during the day. And yes, the parents of the 124 decibel child were presented with a free set of ear plugs to take home.

Visitors also had the opportunity to pan for gold (with a guarantee of colour in the pan), fossick for that special rock, try their hand at rock drilling with an airleg, or show off their skills on a minidigger.

Mark Burroughs at the receiving end of the 'Yell-o-Meter'

The Mines Rescue team was busy all day too, with queues of children taking part in the always popular 'learning the ropes' activity that involves hanging in a climbing harness while each strand of the rope is cut.

Operating mine dump trucks and loaders allowed the public a close up view, as did the remote control bogger. There were also helicopter rides and a static display by the TECT rescue helicopter.

The big attraction for many people continues to be the opportunity to walk down into the open pit. As one visitor said, 'Where else do you get the chance to walk down into an operating gold mine?'

A wide range of community groups took the opportunity to showcase their activities. Newmont's external affairs manager Kelvyn Eglinton said that over the years the Open Day has become a real community event. 'This is a chance for Waihi to show what it's got, it's not just about the mine It's a real buzz to see so many visitors here and a real tribute to the town'.

It's hard work operating the air leg drill.

Newmont Waihi Gold Education Officer Jeannine Wiki coordinated the day. She paid tribute to the hundreds of community volunteers, and the staff from Newmont, Macmahon Contractors, HWE and Boart Longyear. 'It's not just a matter of opening the mine gates on the day, hundreds of hours go in to making sure that the site is safe for the public. We couldn't make this day work without all the help we receive from so many businesses, groups and individuals'.

For one day Martha Mine was noisy, colourful entertaining, educational and exciting. On Monday morning it was once again a working open pit - operating at less than 50dBA.

A Dusting of Lime

Revegetation around the upper batters in the open pit will soon receive a boost with an application of lime and fertiliser.

This vegetation was originally hydroseeded in 2008 and nutrients applied at that time have become depleted. As a first step, lime will be spread with a blower at a rate of one tonne per hectare. This will occur within the next two weeks and is dependent on ideal conditions.

Because the lime is a dry product this activity is likely to appear dusty. To minimise annoyance and reduce the likelihood of drift onto neighbouring properties the operation will take place early in the day in calm weather conditions.

To follow up this initial treatment, Cropmaster fertiliser will be applied in March and again in spring. As this will be in the form of pellets, this activity is not expected to generate much dust.

Hydroseeding

Hydroseeding is a process that quickly establishes vegetation by spraying it as a slurry to a surface.

The slurry, made up of seed and mulch , is transported in a tank and sprayed over prepared ground in a uniform layer. Hydroseeding is an alternative to the traditional dry process of sowing seed. It promotes fast germination and helps to prevent soil erosion .

Hydroseeding is often carried out on sites such as roadsides or motorways after roadworks are completed, golf courses and other areas that are inaccessible or unsuitable for cost-effective conventional methods of seed distribution.

 

At Martha Mine hydroseeding has been carried out progressively over many years on the steep slopes of the open pit walls. The hydroseeding slurry used here comprises a mixture of grasses, legumes, fertiliser and paper pulp. The paper pulp helps to 'stick' the slurry to the bare rock walls and maintain the moisture level of the seed. Hydroseeding is also used at the waste rock embankments and other areas around site where a quick cover of vegetation may be required to help prevent dust generating or to improve visual effects.