Digging out the ore has never really been the hardest part of mining; it has always been finding the deposits in the first place.
Because you can't dig it up if you don't know where it is.
So how do we actually find these deposits?
Nowadays we use magnetic surveys, geo-morphology, historical records of old mines and works, and advanced laboratory techniques to discover just what, if anything, is hiding beneath the soil.
It's very high tech and requires a lot of skill and training to operate the equipment and know just what you're looking at.
But now it seems there is another way.
Plants, animals, and insects are now being considered as a first port of call for miners.
Many people within the industry are fairly well versed in geobiology, how plants and animals may assist miners in finding new deposits.
A whole branch of science – geobotany – examines exactly this.
This field of science in part looks at different plants and what plants may grow well in soils that may have high levels of particular minerals or certain heavy metals.
This field seemed to take off in the 1960s and 70s, and appeared to be a fairly popular branch of mining exploration potential in Russia and the former Soviet Union during this time as well, if the number of research papers and books on the subject are anything to go by.
Even now it still holds some water, and biologically makes sense.
The Viscaria Alpina flower
The technique has been recorded as being used in China since the 5th century BC, and in fact Sweden's former Viscaria copper mine was actually named after the Viscaria aplina flower which prospectors used to discover the deposit, as the flower is known to grow in soils with heavy copper concentrations.
Australian miner Avalon Minerals is currently operating a copper project near this very mine.
Australian natives such as Stackhouse tyronii and Hybanthus floribundus can also be used as lead and nickel indicators according to The Lead Group and to research carried out by CQ University professor Nanjappa Ashwatha and Dr. Poonam Bhatia.
In fact "Stackhousia tryonii is a serpentine-endemic, rare, native Australian plant and is reported to hyperaccumulate nickel up to 55,500 mg g-1 on a dry weight basis," the group explained.
The CSIRO's Ravi Anand has studied geobotany and mining for some time in conjunction with the University of Adelaide, and explained that his group has studied eucalyptus trees and mulgas for mineralisation in their leaves.
The Cooperative Research Centre for Landscape Environments and Mineral Exploration (CRC LEME) was actually a group that has used this method of exploration in the Tanami Desert, in conjunction with miner Tanami Gold at its Coyote deposit at its Western Tanami operation.
It found traditional methods more difficult in the regolith dominated region, as exposed bedrock made up less than ten per cent of the region, and was in some cases up to 100 metres thick, which made it difficult to carry out the usual exploration techniques.
Instead it used geobotanical mapping and biogeochemical sampling – testing the mineralisation in leaves – to map the region.
According to CRC LEME it found a geobological pattern over the Coyote mineralisation, essentially an abundance of bloodwoods and a significant decline in snappy gums, despite its abundance elsewhere.
Careful biogeochemical testing also yielded results.
"Early results of biogeochemical sampling in the Tanami region suggest that biogeochemistry is a promising method of the detection of mineralisation through cover," it said.
CRC LEME officially closed in 2008, with its work now done by the CSIRO and Geoscience Australia.
Plants which thrive in heavy metals are even now being used to help rehabilitate mine sites, with the 2011 Australian Mining Prospect Awards winners for Environmental Excellence, MetalloTek, doing exactly that, by using plants that thrive in heavy metal soils and adapting their biology to grow even better in these conditions.
CQ University's Poonam Bhatia is also doing similar work using 'hyper accumulator plants' from Australia to aid in 'phytoremediation' in India.
"Australian soil is naturally contaminated with heavy metal but the Indian soil has got both natural and artificial heavy metal contamination," Bhatia said.
"Both the countries have native plants that accumulate heavy metal. It is proposed that effectiveness of Australian native plants in cleaning Indian soil would be studied and vice versa."
But it is not just plants that are helping with exploration and to uncover new deposits.
Last month we looked at the world first application of a search and rescue dog for underground coal mine rescues.
This month we are looking at other ways animals, and not just dogs, but also insects, can be used to uncover new deposits or find minerals, in what is more commonly known as 'geozoology'.
And while it may seem absolutely ridiculous, animals and insects have apparently been used since time immemorial to help hunt for mineral and metal deposits.
As far back as the fifth century BC, Herodotus wrote in The Histories of "furry ants" in northern India and Pakistan, later proved to be marmots, which would often unearth gold while digging their burrows and tunnels while the locals collected the material and sifted through their mounds for gold.
Ancient Roman Pliny the Elder also mentioned examples like this in his Naturalis Historia.
In fact it was fairly common knowledge at the time.
A report by Robert Brooks in Episodes outlines how land animals have uncovered metals deposits – albeit unfortunately – by becoming sick with metal poisoning after eating plants and grasses growing over deposits or old, unrecorded mine workings.
"For example, farmland adjacent to Roman lead workings, where several cattle and ponies had died from suspected lead poisoning were found to contain up to 200 µg/g of lead (dry weight) in the grass and pastures of the area," he explained.
Brooks went on to explain how sick animals were discovered to be eating certain plants that were found to have high levels of selenium, and since selenium is often found with uranium, people were able to deduce where the uranium lay due to the distribution of the plants.
It was a "chain of four factors: sick animals – plant indicators of selenium – association of selenium with uranium – the discovery of uranium," he said.
While these examples follow the more geobotanical route, in Northern Europe they are using animals, particularly dogs, in an entirely new way.
In Sweden, Russia, Finland, and Norway, some within the mining industry have trained dogs to find ore bodies.
As with geobotany, the field really began to take off during the 1970s, as dogs were used mainly to find nickel sulphides close to the surface to fulfill demand from the region's burgeoning steel industry.
According to Brooks, some of the best work came out of Finland during this early period, predominately from the Aarno Kahma of the Geological Survey of Finland.
In the mid 60s one trained dog, known as Lari, went head to head with a prospector in a 3 km2 field, and managed to uncover 1330 sulphide bearing boulders at depths of up to 20 centimetres, while the human only found 270 surface traces.
In the same year as the competition the dog also found a copper orebody that later proved to be fairly significant, resulting in its trainer being rewarded $2000 and the dog receiving four sausages.
Following this dog's success Sweden trained four ore hunting dog, and Canada dipped its toe in the water of the field, but found little success.
However the method soon died out as the steel industry suffered and wilted during the 1980s, and exploration for new nickel deposits ground to a halt.
As such since this time is has been virtually unheard of and an unexplored prospecting avenue.
Only now is the technique again coming to the fore.
Swedish company OreDog AB is marketing itself as the world's first dog ore exploration company.
Speaking to Mining Technology, he told them the dogs are used to uncover a wide range of sulphides as well as oxide ores.
Bergman explained that the dogs are trained to sense the smells coming from different ore samples, and how to locate the ore.
"Right now my dog can sense between 20 and 30 different types of ore, they can discover an orebody that is as deep as 12 metres underground," he said.
One of the most recent successes the company had was in late May, when a dog "located an orebody of 100 meter width with at least 300 meter length extension," Bergman said. "We have reason to believe the orebody could be several km long and with extension in depth. We have seen at least 20 meter depth indication of ore. We are now sending in samples for analysis and hope we have an oregrade zinc discovery. Estimates are +5-10 per cent zinc."
In April a possible discovery or a gold orebody was also made.
While it uses mostly German Shepherds as ore sniffing dogs, it also apparently uses Australian Koolies and Belgian Shepherds.
Originally focused on using dogs in Sweden, the company recently branched out into China.
According to Bergman it is also considering opening a branch in Australia.
He told Mining Technology that to date it has been concentrating on Sweden and Scandinavia but has started work in the U.S. and is looking at setting up a company in Australia as well within the next few years.
The company is also developing mobile phone apps to help control field exploration work.
According to Brooks, geozoology and geobotany may also have some crossovers as well.
In Western Australia some native plant species that are hyperaccumulators, such as Hybanthus floribundus have a characteristic smell which some field workers can readily identify; a well trained dog would be able to quickly find these species much faster than a person assisting geobotanists to identify mineral indicator plants, he said.
But it isn't just four legged animals that are making mining a little easier.
Four legs or more
Insects have also long been used for prospecting, particularly for gold and nickel.
In Africa, ancient African civilisations used termites and their enormous mounds as a starting place for prospecting and uncovering deposits.
As termites continually search for water they can often dig down to depths of more than 70 metres and distances of hundreds of metres.
"Termites are nature's little drillers," researcher and University of Adelaide geoscientist Anna Petts explained at the Geological Society of Australia's Earth Science Showcase.
"Termites conveniently bring subterranean soil samples to ground level to construct or fix their mounds.
"So by simply taking a sample of a termite mound, geologists can gain a good idea as to what minerals and metals can be found in the ground beneath it – making it a much cheaper way to undertake preliminary soil testing for minerals exploration," she said.
"More intensive testing can then be undertaken if a site looks promising."
This method was used to find the Vila Manica copper deposit in Mozambique in 1973, while the massive Jwaneng diamond mine was also reportedly found by termite mound sampling.
A DeBeers geologist is believed to have found a piece of ilmenite – a classic diamond indicator – in a termite mound, which lead to further exploration and the discovery of Jwaneng.
The CSIRO's Dr. Ravinder Anand explained that "we can often dissect [the mound's] material and we can send it to the lab for processing and it can provide the clues for mineral deposits that are hidden under sediment".
It has already worked with entomologists to study how this process can be used, Anand adding that it has also studied the termites themselves, to see the concentration of metals in the insects.
In addition to geobotany, Tanami Gold also looked to termite mounds to provide geological information fpr their projects.
"It really has been a case of assessing whether termites in Australia work in the same way [as in Africa] – that is where our research has come into play and it has proved to be the case."
Anand went on to say that the CSIRO has also looked at how spiders and ants may demonstrate deposits underground as well.
While we have looked at how these animals have been used for exploration, they have often played an important role in keeping miners safe.
There is always the canary in the coal mine; used as an early warning system for hazardous gases or poor air quality due to their high sensitivity.
While the future of mining is automated and electronic, it seems there will still be a place for animals on site.