Newmont Waihi Gold operates both the Martha Mine open pit and the Favona Underground Mine in Waihi and has recently started the Trio development project that provides exploration access to the new Trio underground mine in Waihi. We also undertake exploration activities to investigate other areas to determine whether they may contain a viable mineral deposit.
With a population of about 4,700 people, the town of Waihi is situated on the east coast of the North Island of New Zealand. The surrounding area supports horticulture and dairy farming. Waihi is an important service centre for these activities, as well as playing an increasing role in tourism.
Did you know?
Waihi township is within 90 minutes’ drive of half the population of New Zealand, including the major cities of Hamilton, Auckland, Rotorua and Tauranga.
Local areas of natural beauty include the Karangahake Gorge, Waihi Beach, and the coastline north and south.
Waihi township slopes gently down from the foot of Martha Hill to the Ohinemuri River and has an altitude averaging about 90m above sea level.
The climate of Waihi is affected by its local topography. The rainfall in Waihi is relatively high, averaging in excess of 2,100 mm/year. The township lies at the northern end of an elevated basin, which is the source of the Ohinemuri River and its tributaries. The Ohinemuri River flows westwards just south of the town and then through the Karangahake Gorge to the Firth of Thames.
The mining licence was granted for the open pit Martha Mine in 1987. The Favona underground operation, begun in 2004, has been producing ore from stopes since 2006. Martha and Favona produce, on average, around 100,000 ounces of gold and around 750,000 ounces of silver annually. In 2010 the Trio development project began, providing exploration access to the new Trio underground mine.
Together the Martha and Favona mines support a direct workforce of around 350 people. This comprises Newmont Waihi Gold employees and the two major contractors Macmahon Contractors (NZ) Ltd and HWE Mining.
The Martha project was the first major hard rock mining operation to be commissioned following the resurgence of the gold mining industry in New Zealand in the late 1970s. The Martha Mine is situated in the Waihi township, and the processing plant, waste rock embankments, water treatment plant and Favona Mine are located two kilometres away in a rural area. The Trio project is about half way between the Martha and Favona sites, within the area of Union Hill. Because of its location, Waihi mining operations have received a high level of public scrutiny. This is reflected by the stringent conditions set for the projects.
Martha open pit
Mining at Martha is by open pit methods. Ore and waste rock are crushed at the surface facilities area prior to transportation along a 2.7 kilometre conveyor. On arrival at the processing plant gold and silver are extracted from the ore using conventional carbon-in-pulp treatment methods. Waste rock is used to construct an engineered earth embankment to contain the tailings. A water treatment plant treats excess water prior to discharge. Mining within the open pit is currently focussed on the Martha East Layback, a project that will see mining activity continue until 2014.
The Favona underground mine
Late in 2004, construction began on the decline for the Favona underground operation. While some ore was mined during construction, full ore production from stopes began in 2006. Currently Favona ore and Martha ore are both fed to the processing plant and treated alternately.
In May 2011 the Favona Mine had around 20,000 metres of drives, including the decline, and was approximately 335 metres below the surface.
The Trio underground mine
The Trio project is situated under Union Hill and comprises the Union, Trio and Amaranth veins. Construction of two development drives, 590 metres and 790 metres in length, began in 2010. Access to the Trio Mine is through the Favona portal. The Trio project will produce around 1 million tonnes of ore for approximately 200,000 oz of gold at 6-7 grams per tonne average grade.
Our exploration and geological investigations continue. The company invests around $9 million a year on exploration near-mine and in the region.