Correnso

The Correnso gold mine is the first underground mine to be developed under a town in New Zealand. The extent of the deposit, that lies between 250 and 300 metres beneath residential properties at Waihi East, was finally determined by diamond drilling taking place from a 550 metre exploration drive extended from the nearby Trio mine as it was not practicable to locate a drilling rig above ground among residential homes.

Work Began on Correnso Mine Development in Late 2013

Work on the Correnso exploration development drive began in December 2013 and it consists of a five metre by five metre tunnel that features a number of shorter tunnels running from it that are known as 'drill cuddies.' The drill cuddies were used to house drilling rigs that bore down into the Correnso mineralised ore body to help determine the grade, shape and size of the deposit. The information derived from the drilling program was used to finalise the mine design.

Correnso is the First New Zealand Mine to Operate Under a Residential Town

As the Correnso gold mine is the first mine permitted by the New Zealand government to operate under residential properties, it has to carry out its activities under stringent conditions, particularly those regarding blasting vibrations. One of these conditions requires the mine owner, OceanaGold to post a mine plan online at the start of each month outlining the coming months activities. The company also has to feature, on its website, real time monitoring of all vibration events that occur above the mine.

Correnso Blast Vibrations to be Closely Monitored by Residents

The online vibration feature becomes interactive when a mouse cursor hovers over any of the blue dots on the computer screen that represent the locations of ten vibration monitors. This action brings up a dialog box that shows the most recent series of vibration occurrences. All vibrations over 0.75 mm/s will register. The company works hard to ensure the community living above the mine is kept fully aware of all vibrations and the cause of the vibrations.. This action, along with a blast notification program, ensures residents are fully informed every day of any upcoming blasts. The time of these blasts are passed on to the residents living above the mine through text, email or telephone, as well as on the company's website.

Correnso Mine Trialling Tsunado Warning Devices

The company is also trialling a device called a, 'Tsunado.' This device is designed to alert residents living and working above the Correnso mine of any blasting event about to take place. The Tsunado was originally created as a natural disaster alert but was found to be useful as a blast alert device for the mining industry as well. When a Tsunado is kept in a home it receives a signal from the mine immediately before any blasting operation is about to take place underground. This alert consists of a short piece of music. It is believed the Tsunado reduces the startling effect on some residents when a noticeable vibration is felt following a blasting occurrence.
The Correnso mine owner must offer to buy, or compensate property owners on the surface, as a part of the consent given by the New Zealand government for the Correnso mine to be developed under the town of Waihi East. The company has to make an offer to affected landowners that they will, if required to do so, buy the affected property at its market value. If the owner prefers the company must make an ex gratia payment to the landowner equal to five percent of its market value. If the property owner chooses to sell his or her property at market value they must also be paid an 'inconvenience payment' and given assistance with any moving and legal costs.