Mission Mine Tailings #4

Borderland constructed approximately 11,000 LF of new 24” HDPE discharge gravity flow pipeline between the mill and a tailings storage facility.  The new gravity line required significant earthwork and grading to establish the new horizontal alignment and vertical profile for the transmission pipeline.

Also as part of the project, a pump station was installed to recover, pump, and return decant water to the mill.  The decanted water is returned to the mill via an 18” HDPE pressurized pipeline.

Project Details

Location: near Town of Sahuarita, Pima County, Arizona
Construction Cost: $2.7 M
Owner: Hanlon Engineering (ASARCO, LLC)
Project Delivery: DBB
Scope: Lift Station and Transmission Pipeline

The pump station and transmission pipeline project included earthwork, grading, paving, storm drain, rip-rap, fencing/gates, 84” diameter x 10’ deep drop structure, vaults, pads, vertical turbine pumps, hydro gates, trash screens, conduits, wiring, breakers, disconnects, lighting, enclosures, flow meters, pressure indicators, and instrumentation.


  • 172,530 CY of Earthwork/Grading
  • 10,850 LF of 24″ HDPE Pipe Line
  • 7500 LF of 18″ HDPE Pipe Line
  • 3600 LF of DC HDPE Pipe Line
  • 570 LF of 18″ CMP
  • 1065 LF of 24″ CMP
  • 570 LF of 24″ Arched SRP (28″x20″)
  • 705 LF of 42″ CMP
  • 20,825 LF of 24″ HDPE SDR-17 Pipe
  • 7460 LF of 18″ HDPE SDR-17 Pipe
  • 3572 LF Dual Contained 18″ SDR-17 Carrier x 24″ SDR-32 Containment
  • 375 LF of 24″ SRP Sleeving
  • 740 LF of 36″ SRP Sleeving