How sensors help optimize the copper leaching process

Innovex, a Chilean technology services company, developed sensors to measure humidity, temperature and other variables in leach pads, serving miners that are using hydrometallurgy and increasingly rely on technology.

BNamericas talks with Innovex’s operations manager, Gonzalo Santamarina, about how the sensors work and what miners will gain from the collected data.

BNamericas: Why did you decide to provide technological solutions to the mining sector?  

Santamarina: We saw that the process of obtaining copper through leaching pads, which yields about 25% of the metal, was a stage with low technological development and that efficient monitoring was needed.

BNamericas: And what kind of experience have you gained in the sector?

Santamarina: We carried out the first work for Mantos Copper's Mantoverde, measuring temperature and humidity in the leach piles with our sensors that were buried in the piles. We are still there with staff on the ground, working full time.

In mining, we measure temperatures at different leaching heap levels, humidity and the pressure in the lines of the drippers that are installed on the heaps. We also measure oxygen levels, the water table and the flows in the leaching systems underneath the piles, the level of the pools, temperature and aeration system flows. Our tests take about six months.

BNamericas: What are the benefits of using sensors in the leaching process?  

Santamarina: Before, everything was done manually. But our teams get information from the leach pads in real time and every five minutes. That is, instead of measuring only once a day, or every two days, clients can constantly measure and that allows knowing at what rate, which sectors you are watering and which sectors could collapse.

For example, if a drip line is down or near zero, it's probably because a hose has been disconnected and flooding is occurring somewhere. This opens the possibility of collapse. Consequently, our work improves the efficiency and safety of the mining operation.

BNamericas: How do you install the technological infrastructure to measure remotely?

Santamarina: The installation of the hardware, sensors and transmission systems is very simple. We know that working on leach pads is exhausting, with long walking distances and muddy roads. That is why we develop lightweight modular equipment that is easy to install. In places without internet, we install the equipment to transmit directly and wirelessly to the receiving device that may be in the same pile, in an isolated place or a control unit.

And the solution can be in the cloud, on our server, or in the company's IT infrastructure. In case of a lack of connectivity, we may transmit via our satellite modules.

BNamericas: How is heap leach piping monitored?

Santamarina: The piping systems on the pile allow aeration. We have a lot of experience in visualizing the state of these pipes, with inserted cameras. We can detect if they are collapsed due to the weight of the pile and check if the aeration system is working with the right airflow and temperature.

BNamericas: How does the alarm system act when the parameters are not met?

Santamarina: With the configuration of alarms, setting the values and ranges for the operation, it can be quickly detected if something is out of range. The alarm sends a message via email or to the client's cell phone so that corrective actions can be taken, which could be a manual cut-off of the solution flow or other automated actions.

For example, in case of a failure in the flow of the pipes, our team can automatically stop that flow by activating valve closures. Through our web applications and mobile apps, workers can access information in real time.

BNamericas: And how does your business model work?

Santamarina: We own and operate the equipment. We take care of equipment maintenance, calibration and correct sensor operation. We charge a monthly maintenance and data delivery fee. We also have software that checks several times a day if the sensors are working to detect possible failures in advance.

BNamericas: Which Chilean mining companies have relied on your services?

Santamarina: We have run tests at Centinela, Escondida, Radomiro Tomic, Zaldívar, Spence and Lomas Bayas. We currently have a contract with Zaldívar. We also carried out successful measurement tests with SQM's iodine batteries. So the next step could be lithium.

BNamericas: What are the main failures that occur in leaching processes?

Santamarina: More frequent is inhomogeneous watering at the different points of the pile, which are produced mainly by watering system disconnection or failures, either because a hose was crushed, collapsed or disconnected. This can cause settling, but we quickly detect that, as well as collapses in the aeration systems, avoiding interruptions and delays.

BNamericas: Can Innovex's software be integrated with other technological tools?

Santamarina: Our software is very user friendly, it is already in version 3.0 that allows generating automatic reports and graphs with all the historical data, sorted by dates and periods.

In addition, it can generate tables with all the information, put together statistics, etc. With our API we allow any other software to access and connect to our software, since much of the leaching data is used for other mining processes.

BNamericas: How much do your services cost?

Santamarina: It varies a lot, as 30, 40 or 500 sensors can be installed in a pile. As a reference, a basic installation with around 30 sensors has a monthly cost of 360UF [index-linked units, 12.7mn pesos (US$15,600)].