In May 2016, an aquifer capable of producing between 400–1,000 l/s through a 36” feed line was identified 34 miles northeast of a large gold mine in Zacatecas, Mexico. Due to the need for additional fresh water to support mining operations, the Reliable Controls Team was contracted to commission the project, including 15 Water Wells, 3 Holding Tanks, 2 Booster Pumping stations and associated equipment. The well field consisted of 4 branches, with each branch having between 2 and 5 wells.

The commissioning was completed in three stages. 

Stage 1-First Water

• Planning
  
• Control Systems
  
• Care, Custody & Control
  
• Contingency Planning

In the First Water Stage, the RCC team helped develop a plan to achieve first water with minimum requirements, all while remaining environmentally conscious. The plan included safe and efficient pipeline flushing, addressed items associated with tie-in to the existing piping, controls, and power; the team also ensured that the control systems infrastructure was in place and functional for first water needs. The contingency plan assessed project requirements and provided solutions to mitigate risk. Our team also provided a tagging system that outlined all care, custody and controls procedures of each device.  

Stage 2- Pre-Ops to Turnover

• Pre-ops & Commissioning
  
• Controls Systems Owner
  
• Documentation Tools

In the Pre-Ops to Turnover Stage, RCC developed an effective testing system to ensure a safe and efficient verification and validation process of components including mechanical, piping, electrical, instrumentation, and controls. Functional testing (PLC/HMI control, interlocks, sequencing) was performed to ensure project design standards were met.  In this stage, the RCC team also provided solutions for Network Hardware Configuration, Controller Settings, PLC Logic & HMI Functionality, Correct Fiber Optic Paths and Termination.

The project was split into 4 Unit Phases to address urgent Fresh Water needs to enable the mine to continue to operate at full capacity.
Unit 1 involved the well field Branch 6 commissioning.  This branch, made up of 2 well sites, is the closest to the mine. Branch 6’s two high production wells (58 l/s each), feeds water into a Secondary Holding Tank located at the Secondary Booster Pump Station.  The Booster Pump Station consisting of two 400HP fix speed pumps (Primary/Standby), supplied interim water to the mine while the rest of the well field was constructed and commissioned.

Units 2 – 4 were comprised of the construction, pre-commissioning and commissioning of the remaining 13 wells on the three most northern Branches of the well field, the Suction Tank and Primary Booster Station for this portion of the project. These wells range in size with the smallest well delivering 18 l/s and the top producer pumping at a rate of 90 l/s.  All three Branches feed into the Suction Tank with a 570 l/s (2,052 m³/h) total flow.
The three branches and Primary Booster Station were commissioned as follow:

• Branch 3 with 5 Well Sites and a capacity of 236 l/s with two of the four 900 HP Booster Pumps
  
• Branch 2 with 4 Well Sites and a capacity of 130 l/s with third Booster Pump
  
• Branch 4 with 4 Wells Sites and a capacity of 205 l/s
  
• The final Booster Pump was commissioned just prior to the Performance Test due to procurement delays

Pre-commissioning loop and functional testing was performed using a tablet based application called InControl which allowed RCC’s field teams to connect to the well and booster pump station PLCs wirelessly.  Technicians used the app to test all field connections to the PLC and functional test pumps and valves while standing next to the equipment.  This allowed the teams to test remote equipment prior to the connection of the fiber optic network without having to deploy an HMI computer in the field.
Reliable concluded a final three-day Performance test during the first week of February 2017 with the following results:

• Produced 500 – 520 l/s over the first two days of the Performance Test utilizing Branches 2, 3 and 4 with the Primary Booster Station (Max flow of 570 l/s).
  
• Adding Branch 6 to the Performance Test on day 3 took the total flow for the Northern Well Field project up to 610 - 630 l/s (2,200 – 2,270 m³/h)
  
• Total feed over the first 48 hours of the Performance Test Period: 86,763 m³.

Some of the challenges experienced during the project were as follow:

• Relocation of the Substation, Suction Tank and Primary Booster pump station.
  
• Weather conditions, rainy season with higher than normal rainfall caused trenched to flood and halted construction efforts.
  
• Low flow (116 l/s) during Phase 1 not sufficient to enable a proper flush of all the debris in the 36” feedlines feeding the Gravity Feed Tank.
  
• Availability of construction spares.
  
• Procurement and delivery delays.
  
• Intermittent HV supply failures during the course of the project.
  
• Milestone changes due to water needs for the mine.

Stage 3- Completions & Optimization

• Turnover
  
• Deficiency Management
  
• Operator coaching & Training
  
• Operational Optimization & Other Recommendations 

In Stage 3, RCC assisted in driving project completion, provided full project documentation, a combined discipline punch-list, operational training and final transition to the operations group. We also provided recommendations for optimization based on our findings during project experience. 

These notable results were achieved by a multi-national Reliable Controls Team! We welcomed members from Argentina, the US and Peru to join us on this project in Mexico. We are proud of the project's outcome and appreciate everyone's hard work and dedication once again!