Mine dewatering efficiency boost with new Audex pump
A well-matched submersible pump saves up to 22kW of electricity per hour, with less cycling reducing the shock stress to switchgear and pipework.
Overview
A 37kWh submersible pump is successfully replaced by a 15kWh Audex, dewatering a mine in Care & Maintenance (C&M) mode.
The operation includes two pontoon-mounted submersible pumps and a borehole pump lifting up to 300m3 an hour to the surface, a head of 90m.
Challenge
Part of the dewatering process involves moving water from the deeper part of the mine to the base of the borehole pump. Originally, this was done with two 37kWh submersible pumps mounted on a pontoon, in a duty-standby arrangement. Most of the time, they would cycle on and off daily, triggered by the high and low-level float switches.
The mine management team had delivered some cost savings by installing diverter pipework to feed some water directly to the borehole pump. This enabled them to look next at the submersible pump capacity.
"For everyday that we run the Audex instead of the older pump, we save enough electricity to power three average houses"
Mine Manager
Removal of old 37kWh pump
Solution
The mine’s manager saw the potential for an Audex pump, and it was determined that a 15kWh model would handle the duty for long periods throughout the year. This could replace one of the 37kWh pumps, leaving the second one in place as a backup.
There was an unknown; the existing pipework was installed using a mix of materials and has several bends, making it difficult to calculate the flow resistance incurred. This issue was side-stepped when Atlantic Pumps increased their hire fleet and hire-to-buy options, allowing the mine to test the real-life performance over a 6-week period.
After a few days of running the old and new pumps together while determining the best sensor level settings, the new Audex (replacement of "No2_Pump") is running solo. It stops automatically on low level (0.2m), and is running on a six-day cycle at current inflow rate. A remote manual start can be initiated at levels of between 0.4 and 0.6m to optimise off-peak electricity tariff savings.
“I was impressed with the quality and value of Audex pumps when I saw them at Hillhead show. Working with Atlantic we are delivering energy savings; this is without compromising reliability. I look forward to working with Atlantic on future projects”
UK Mine Manager
Results
Water levels remained tightly controlled with the Audex running the dewatering on its own, and optimisations of the float switch settings have resulted in minimal on/off cycles.
Assessing the performance, the mine manager confirmed a successful outcome to the trial, saying "the pump duty is perfect, just beating the inflow".
Accurately matching the pump to its duty results in energy and maintenance cost savings, in addition to asset health longevity. As our client explained, "less cycling means less shock to switchgear and pipework"
- The smaller pump enables easier installation and relocation, and the client was able to install the pump without hiring in a telehandler.
- Modern, high-efficiency pumps, along with careful motor and impeller selection optimised the motor’s efficiency (saving up to22kWh an hour)
- Reduction in ongoing energy use, and less expense on wear parts.
Chart: No2 pump replaced with an energy saving Audex pump in late May; fewer starts equal less energy and wear. No1 pump remains on standby for heavy deluges and maintenance backup. Image courtesy of N Hardie, used with permission Removal of old 37kWh pump
