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Mexico: increasing mining efficiency with telemetry

Monitoring a leaching heap irrigation system in a copper mine in Sonora

 

Intro
Heap leaching is an industrial mining process to extract precious metals such as copper from ore by applying a specific chemical solution through drip or sprinkler irrigation. This solution will absorb the specific minerals. Once sufficiently enriched the solution is processed to remove the desired minerals.

Task
While instrumentation is rather common in many parts of the process, particularly in the final stages of the minerals' removal, it is not common in the field at all. Conventional real-time systems need continuous power as well as well as landlines and lots of other cabling, consistently in danger of damage. The dynamics of the leaching pads also present a challenge for these types of conventional systems, which usually are powered by large solar systems.

Bad irrigation of the leaching pads lowers the efficiency of mineral extraction. Standard supervising of pad operation involves human operators walking the field every day to take one or two readings of the pressure at irrigation valves and adjusting it, if needed. Response time to any problem is usually 12 to 24 hours, creating lots of uncertainty for the operations manager of the real performance of the irrigation system.

The ADCON distributor Agrienlace was tasked by the „Piedras Verdes“ mine in the state of Sonora with the design and installation of a continuous monitoring system for flow and pressure at key distribution points of the irrigation pipes to enable the operations manager to make sure that the system operates as planned at all times, and to largely reduce the response time should any discrepancies occurr.

Solution
The ADCON Telemetry equipment with its complete range of compact, low-power RTUs and sensors provides a sustainable monitoring system to continuously track various parameters involved in the leaching process. A first acquisition included monitoring of flow and pressure on the main lines at 23 sites. Since the mine was not covered by cellular communication, UHF was the only solution.

ADCON A753 addWAVE UHF stations, equipped with a Modbus interface, were connected to 8” SS316 electromagnetic flowmeters, outputting instant and total flow. To monitor pressure ADCON PA1 manometers with a range of 0...10 bar were installed. Once the system had passed an initial testing stage with flawless performance, the network was increased to 28 sites, now with even larger 18” SS316 flowemeters. In a subsequent third stage another network was installed to monitor the irrigation cells. Again, ADOCN PA1 manometers with a range of 0...10bar were installed, adding RG1 rain gauges and combined soil moisture, soil temperature and soil conductivity sensors to keep an eye on the oxygen concentration in the minerals.

 

Summary
Keeping the leaching irrigation perfectly within the optimum pressure range, reacting quickly to low flow alarms to fix problems much quicker than before, the client has experienced an increase in extraction efficiency so large, that the entire investment for the monitoring network had paid off within the first ten months of the project. The interruption-free historic data set generated by the system and stored in addVANTAGE Pro allows operations to have a trustful reference data base of their field values, delivering much better results than the previously „hand-made“ reports.

Through the continuous support of Agrienlace the project continues to grow, and new applications are being incorporated into the system, seeking to give to the end user additional tools to further improve his efficiency.

 

ADCON Products deployed in this project:

Case Study Summary

Application
Monitoring copper heap leaching

Location

Sonora, Mexico

Products deployed
A850 Telemetry Gateway
A753 addWave UHF
ADCON RG1
ADCON PA1
Stevens HydraProbe

Participating Organization
Piedras Verde Copper Mine

Parameters recorded
Pipeline flow, instantenous and total
Pipeline pressure
Soil moisture, temperature and electrical conductivity
Precipitation

Participating Consultant/Integrator
Agrienlace S.A. de C.V.