Towards the automated mine

Taking humans out of the arduous, dangerous environment of mines is an important goal for the automation sector, with open-cast sites likely to see the earliest benefits. Andrew Czyzewski reports

The mining of minerals must surely be the most demanding, dirty and dangerous job in the history of human industry. That’s not to take away from the millions of workers who have toiled for the good of civilization. But if ever there’s justification for full automation, it must be mining.

Indeed that’s the goal that many of the big mining players are now racing towards. In truth, the industry has been very slowly heading that way for decades. Most mines are pretty desolate of humans, with vast sites criss-crossed by trucks.

In the not-to-distant future though, the sites could be run entirely by control centres thousands of kilometres away.

‘The mining industry is working towards autonomous and remote operations to achieve productivity gains and safety improvements. This requires all systems and applications to be integrated to strengthen and improve work process so that the complete value chain from the mine to the market is controlled in the most optimal way,’ said Ricardo Hirschbruch,  a process automation region division manager with ABB – a company that has been involved with mining automation since 1985.

‘The mining industry is working towards autonomous and remote operations to achieve productivity gains and safety improvements

Ricardo Hirschbruch, ABB

Virtually every stage in mining can potentially be automated, including the direction of drilling, the loaders that scoop up the ore, the trucks that transport it and the initial grinding and processing.

But generally speaking, it is the great open pit terraced mines that will be the first to achieve full automation and those that extract soft ores rather than hard rocks and minerals like diamond.

‘When talking about automation one needs to consider the degree of continuous process,’ said Clive Colbert, technology manager for ABB’s mining business unit. ‘Soft rock mining allows for a higher degree of continuous process that leads to higher automation compared to hard rock, that tends to represent more discrete process and less automation, especially when linking the process together.’

Naturally, there are different approaches to mining automation.Anglo-Australian miner Rio Tinto has a fleet of self-driving trucks which use satellite positioning to carry nearly 300 tonnes of ore along predefined routes at its ‘Mine of the Future’ site in Western Australia.

The trucks communicate their position and speed to each other using ‘vehicle to vehicle’ wireless links, so that they can co-ordinate their actions, for example at junctions.

By contrast Brazilian miner Vale, along with automation contractor ABB, favours a ‘truckless’ system of very long conveyor belts that can move and change direction.

Vale has invested $8b to automate part of the world’s largest iron ore mine at Carajás Serra Sul, in the heart of the Amazon rainforest.

The ore is very rich in iron there, containing some 66% metal and the area is estimated to hold enough reserves to carry on mining for the next 400 years.

In 2011 Vale achieved a record output of 109.8 million metric tons of ore. When the new automated section, dubbed ‘S11D,’ is fully operational in 2016, they hope to increase production to 230 million metric tons.

Once extracted from the ground, the iron ore is collected by excavators and deposited in mobile crushers. The crushed ore is then fed onto conveyor belts, which takes it to the processing plant. When completed there will be 37 km of conveyor belts distributed around the mining area, including branches that will connect to the main 9.5-km trunk line that in turn goes to the processing plant. Most of the ore is taken from there by rail a distance of 690 km to the port of Sao Luis on the Atlantic coast.

‘There is a requirement that the conveyor system is able to crawl as the mining operation moves,’ said Clive Colbert, Technology Manager for ABB’s Mining Business Unit. ‘The conveyor belt has a number of motors that must be controlled to move the belt to the required location … GPS coordinates are used for precise location.’

ABB says this effectively takes 100 off-highways trucks off the site thereby cutting the amount of waste, such as tires, filters and lubricants, and reducing diesel consumption by 77%.

ABB’s solution also enables automation of the recovery and piling of iron ore by controlling and positioning equipment through real-time satellite positioning, GPS and 3D scanning.

Sequential recovery and pilling steps are common at open sites, because there are multiple materials handling steps during the processing of the ore. It is also usual to pile the final production in stockpiles, waiting to be loaded in trains to transportation.

ABB is trialling the concept of autonomous yard machines to carry out this task through a control centre.

‘It’s a challenge for the Carajás region, because of the kind of weather with constant rain, which frequently causes sliding on the iron ore piles. To address the problem, ABB will use 3D scanners to essentially watch the piles virtually and GPS to have a precise positioning and control of machines in the field to avoid the risk of collisions between machines and between machine and stockpile,’ said Hirschbruch.

‘Soft rock mining allows for a higher degree of continuous process that leads to higher automation compared to hard rock

Clive Colbert, ABB Mining Business Unit

To coordinate the entire operation over such a vast site and manage the streams of data, ABB will deploy its tried and tested, 800xA integrated automation platform – although on a much larger scale than ever before.

‘To get an idea of the magnitude, the plant should use at the end of project approximately 250 controllers communicating simultaneously to each other, developing the distributed intelligence,’ said Hirschbruch.

‘From the plant control centre it will be possible to monitor and control every single piece of equipment in the plant. That’s being designed to maximize the synergy between multiple disciplines — such as maintenance, engineering, production, quality and safety — and to be the single interface for those in the field, forming a collaborative base to make decisions.’

Clearly there’s some way to go yet before we reach a situation where we can sit back and wait for the processed raw material to land in our laps ready for use. Plus there are even more challenging environments than Carajás. But it seems that mining could be turning into an entirely desk-based profession – something unthinkable decades ago.