Oyu Tolgoi employees underground

What does it take to mine 2km underground?

Four technologies you’ll see in copper mines of the future

Last updated: 9 September 2019


It’s a 15-minute elevator ride almost two kilometres down Resolution Copper’s “No.10” mine shaft in Arizona, US. At these depths, temperatures can reach nearly 80°C.

And while it isn’t the world’s deepest mine, the project – which is currently undergoing approvals – offers a glimpse into the future of copper mining. As high-grade copper deposits become rarer, miners must venture ever-deeper, in inhospitable conditions, to access the metal.

Resolution employees underground

“Copper has just become a lot harder to get, and we’re relying on technology to keep dealing with that decline in grade,” said Craig Stegman, vice president Operational and Technical Support in Rio Tinto’s Copper & Diamonds business, in an interview with The Wall Street Journal in June 2017.

To access one of the world’s largest untapped copper deposits, the Resolution team is going to new lengths to create a safe and efficient mine. Here are four technologies the team plans to use to mine copper ore deep underground:

1. Powerful sensors

Tens of thousands of powerful electronic sensors will monitor everything from ensuring employees aren’t overheating, to monitoring the condition of equipment and tracking rock movement during the caving process.

The sensors need to be extra-durable, reliable and designed to withstand the high underground temperatures.

2. Sophisticated data analytics

Terabytes of data will travel wirelessly from sensors to a central database on Rio Tinto’s network and be fed into sophisticated analytics systems. These systems will help monitor tasks ranging from underground blasts to the movement of autonomous vehicles.

Rather than one person viewing data about a specific part of the mining process, information from across the mine can be sent to a single place where experts can obtain a more holistic view of operations.

Oyu Tolgoi employees underground

The holy grail of caving

Revolutionary technology – known as Cave Tracker – is making underground cave mining operations safer and more profitable.


The Cave Tracker system uses a series of trackers and detectors placed in and around the orebody to track the rock three-dimensionally inside the cave as it moves in real time. The system can transmit signals through two hundred metres of rock and will continue working remotely for many years.

To ensure the trackers could withstand the immense force of rock, the inventors brought in a NASA engineer to assist in designing a tough outer shell to protect the trackers deep underground.

3. Battery-powered and autonomous vehicles

Autonomous vehicles will be used throughout the project. For example, automated loaders will transfer ore from the mine’s extraction points underground to autonomous ore handling systems.

The team is also working with equipment manufacturers to address one of the challenges of using existing electric load, haul and dump vehicles underground. Traditionally these vehicles needed to be connected to a power source by a giant cable, which restricts their use and reduces overall operational flexibility. Now the team is working with suppliers such as Caterpillar, Sandvik and Komatsu to create battery-powered vehicles that don’t require the electric cable.

4. Giant climate-control systems

At these depths, the rock temperature is nearly 80°C. Without cooling, an average person would not survive more than a couple of hours.

The team has had to undertake significant engineering and construction work to create an environment suitable for people to work in. This included engineering a complex ventilation system – like a giant air conditioning unit – which keeps the air in the mine breathable and at a comfortable 25°C.

Read more in The Wall Street Journal's article “Mining a mile down: 175 degrees, 600 gallons of water a minute”, available to subscribers >

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