High wealth off a small footprint

Mining earns very high wealth off a small footprint. No other land-use earns anywhere near as much as mining does.

The reason for this is simple. Minerals are concentrated into economic ore deposits in very few places, and then they have to be found. As the easier-to-discover and access resources are developed, the search proceeds to resources that are more difficult to detect, and more difficult to extract, with upward pressure on costs. Exploration and mining technologies continue to advance to meet these challenges.

 

The wealth

OceanaGold has calculated that it would take more than 700 years of farming on the footprint of the Macraes gold mine in East Otago to earn the same value as that projected for the total life of the mine.

Chatham Rock Phosphate has carried out a similar calculation for their project to mine phosphorite nodules off the seafloor of the Chatham Rise, in the Exclusive Economic Zone, east of the South Island of New Zealand. Their figures suggest that it would take 1000 passes of a trawl net over an area of seafloor to earn the same value as one pass for the rock phosphate over the same footprint.

 

The footprint

The total area of mining on land in New Zealand, including quarries, has been calculated at 0.05% of New Zealand’s total land area. That is a working footprint of 134km2 compared to a land area of 268,000km2. To understand how small a footprint this is, think of a 5mm x 5mm square on an A4 page – that is the comparison.

On the West Coast of the South Island, a traditional mining region in New Zealand, the mining footprint is 14km2, or 0.06% of the regional area of 23,000km2. That mining earns directly and indirectly 40% of the region’s GDP, a very significant percentage of the local economy.
A large opencast mine, e.g., Macraes, has a working footprint of 300-500 ha, or 3-5km2. An underground mine typically has a surface expression of between 5 ha and 20 ha. The Stockton coal mine is an exception to the rule, having a working footprint close to 1000 ha, or 10km2. The reason for this is that mining has a long and continuous history at this site, since 1885. The management of the site is a “legacy issue” – it will take time in the harsh climate of sub-alpine Westland to bring this site into the same pattern as most contemporary mines in New Zealand. Learn more on Mining 101.

The mine footprint is constantly changing because site rehabilitation begins when mining begins, and continues until after the mine closes. As mining proceeds in one direction, land that is no longer needed for mining is returned to a former or desired land-use. We borrow the land, mine it and return it. Mining is a temporary land-use. Learn more on environmental management.