Chile: big mines, big data and big geology...by Mark Patton

Mark at Rio Blanco 

Following the trip to Alaska in August, the final residential for the 2015 Camborne School of Mines Mining Professional Programme began in Santiago, Chile, only 12 weeks after getting back from the previous one. Thankfully it was to the southern hemisphere, because as I touched down to 25° in Chile it was -25° in Fairbanks.

We spent the first 5 days in Santiago, visiting the Consejo Minero to discuss the current state of mining in Chile, the Sandvik factory to check out some of the machinery workshops and one of the local universities (so the Professor could make a few contacts). All of this interspersed with teaching sessions, presentations and the receipt of details of more presentations to be made during the course of the visit.

Early starts had been a feature of the Alaska trip but the 3am departure to the airport for an internal flight north trumped all of them. Santiago had been dry, but our new location Calama, located in the Atacama region, was more so. It was our base for some incredible mine visits.

First up was the Centinela Mine run by Antofagasta, an open pit copper operation about 40km south of Calama. You couldn’t quite call the equipment shiny, but it was relatively new and the operation was clearly streamlined. Everything was observed from a distance so we had a chance to get a good overview of the full mining process, from the pit, through to the processing mill.

Prepared for the plant at Chuquicamata

The second visit was to the biggest open pit copper mine in the world – Chuquicamata, operated by the Chilean national copper company CODELCO. It’s huge, as are the waste rock mountains that form much of the scenery on the drive in. Where Centinela was new and shiny, Chuquicamata has been on the go for a considerable time and the operation is sprawling. Here we got to see the pit and the processing plant in all its glory and the highlight was watching smelted copper get poured into moulds. It’s surprisingly runny. When cooled these lumps of copper are then used as the anode in the electrical process where the copper is purified to 99.99%.

Our mid residential day out was to the Atacama Desert itself. It was a long drive, mostly up on the way there. Previous experience of high altitude has always involved rugged Alpine style peaks so it was bizarre to find out we were at over 4700m and pretty much surrounded by flat desert. The scenery was spectacular though. Too much running about taking group photographs resulted in a spot of altitude sickness, but thankfully the pounding head and nausea eased on the drive back down to Calama.

The Atacama Desert

As a deviation from looking at big holes (and since we were learning about the whole mining life cycle not just the digging it out bit) we spent a pretty fascinating half day at the Anglo American tailings management facility for the Los Bronces mine. These structures are used to contain the residue left over (the tailings) from the mineral processing. Looking down at the tailings pond with its 80m high dam we were informed that by the time the mine closed, the spot we were standing on would be part of the facility and the dam would be 250m tall. This facility sits approximately 5km across a valley (which is filled with vines) from a similar tailings pond operated by CODELCO. Both of these are just 25km north of Santiago...

We returned to the superlatives theme for the trip with the next visit when we called on the biggest underground copper mine in the world. El Teniente is also operated by CODELCO and also relatively close to Santiago. Despite being close however we managed to be late, and as they thought we weren’t coming, the mine had cancelled the trip. Fortunately no one had gone too far and our guide was re-conjured, a spare bus acquired and we set off underground. But not before we had spent over an hour in the bus getting to the portal.

Underground crusher at El Teniente 

The part of El Teniente we visited is being mined by a process called block caving where underground blocks are undermined and allowed to collapse under its own weight, a method not many of us on the course had been exposed to before. One of the issues that can be encountered with this method, and an occurrence at El Teniente, is hang ups at the draw points. This is where a block of the ore gets stuck at the place where the trucks are supposed to access it for transporting to the crusher. Being underground when they carried out a secondary blast (a smaller explosion used to break up theses stuck blocks) was another first for me. We were just round the corner and I was in the process of rolling the second ear plug when the punch hit my chest at the same time as the boom hit my unprotected ear. Fortunately my vocal reaction was muffled.

The last trip of the residential was to another CODELCO operation, the Andina Copper mine, approximately 70km north east of Santiago. Before the mine itself, we stopped in at the operations control centre at Los Andes to see a cutting edge use of ‘big data’. The deputy director, Herman Aguirre, has set up a system where operations at the Andina mine can be monitored and graphically plotted in real time from any coffee shop in Santiago (or the world for that matter). The data he collects can be used to improve the productivity of the operation and the savings, on a scale that CODELCO operates at, can run to tens of millions of dollars, all using open source software.

Bid data in Andina Mine control room

Herman accompanied us to the mine proper, which was approached from the bottom up for a change (as opposed to arriving at the rim and looking down). We did eventually reach the top and from there, as well as looking down on Andina, we could look over the other side of the mountain to the Los Broncos mine which is also exploiting the Rio Blanco copper deposit. This was the final ‘biggest’ of the trip. The Rio Blanco was described by a CODELCO geologist as a planetary anomaly, it is so big. With two major copper mines working at it at once it would need to be.

The final event of the trip (all part of the assessment for the course) was a debate with the motion: This house believes that Chile will continue to lead global copper production over the next 25 years. Despite an emotional and powerful opening statement by those against, the motion carried, which was hardly surprising given every one in the room believed it to be true.

Chile is a fabulous country with stunning geology, better food that Alaska and airport security that is reminiscent of Europe in the 80s. I fully intend learning Spanish and going back for a more leisurely visit, maybe heading south next time.