Mine Site Rehabilitation Solar Pump System

Customer: Department of Environment and Heritage Protection

Location: Mount Chalmers Gold Mine – Mt Chalmers, QLD

Case Study ID: CS-38

Date: December 2017

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Overview

Dowdens Pumping & Water Treatment’s Rockhampton branch was engaged by the Queensland State Government’s Department of Environment and Heritage Protection to deliver an efficient solar pumping system at the disused Mount Chalmers Gold Mine, located 15km North-East of Rockhampton, QLD.

The Department of Environment and Heritage Protection (EHP) has managed the critical environmental issues at the Mount Chalmers Gold mine since the former operator Affinis Pty Ltd was placed into liquidation in December 2014.

EHP is also supported by other government agencies, including the Department of Science, Information Technology and Innovation (DSITI), who provide scientific advice on technical aspects of site management. The primary ongoing focus is to prevent any discharge of contaminated water from the site.

Utilising a combination of Grundfos Solar Water Solution products (inverter/pump / solar panels) appealed to the Department of Environment and Heritage Protection as it meant Dowdens could supply a system that not only costs less to install and maintain but significantly can pump a larger volume of water under solar power. Put quite simply, the ability to run large 415V pumps capable of greater pump duties is making the decision to ‘go green’ and install solar-powered systems more attractive in the current climate for miners and farmers alike.

The Problem

As part of this site’s ongoing rehabilitation process, the Department of Environment and Heritage Protection needed an efficient solar pumping system to recirculate contaminated mine water collected from a sump back into the central pit, thereby eliminating any contaminated mine water runoff from the site.

With limited mains power available to the site, solar power was a perfect fit for this pumping application. Solar-powered pump solutions are continually improving, none more so than Grundfos Solar Water Solutions. During initial site inspections, the pump’s required operating duty was calculated to be 13L/sec @ 18.5m Total Head.

To meet these high flow requirements a Grundfos Solar Inverter (RSI) was selected to power the Grundfos R Series Submersible Pump that the Department of Environment and Heritage Protection already had onsite. The Grundfos R Series is a Stainless Steel pump capable of handling the low pH, slightly acidic mine water (measuring between 2 & 3 pH) needing to be pumped.

Our Solution

Dowdens Pumping and Water Treatment Rockhampton initially visited the site to establish the location of the solar arrays and calculate pump duty. Once known, the following components were sourced and prepared for installation: 36 x Grundfos Solar Modules, 2 x Fixed Array Frames, Grundfos RSI Inverter & Sine Wave Filter and 200m of PN10 Poly Pipe.

The Grundfos Pump was attached to a specialised float on the sump surface. The pump starts & stops via a level float switch mounted on a 4m pole that can swivel over to the sump’s bank should any maintenance be required.

Local contractors were then engaged to complete the site earthworks and trenching needed for all electrical conduits. Once the solar array support posts were cemented in place, Dowdens Pumping & Water Treatment Rockhampton’s team assembled the SolarTerrace Array Frames and mounted the 36 solar modules ready for the electrical components to be installed. Electrical contractors completed the electrical fit-out.

As part of these works, Dowdens Pumping & Water Treatment Rockhampton branch delivered the Grundfos Solar Inverter Sine Wave Filter & String Connection Box to the workshop to be mounted in a powdered coated, lockable enclosure with sufficient ventilation to ensure the inverter remains cool during the day. All commissioning of this system was undertaken by Dowdens Pumping & Water Treatment Rockhampton branch.

Key Components

36 x Grundfos Solar Modules
Grundfos R Series Submersible Pump
Grundfos RSI Inverter and Sine Wave Filter
2 x 18 SolarTerrace Module Fixed Array Frames
Specialised Float to suspend the Grundfos Submersible Pump on the sump’s surface
200m of PN10 Poly Pipe

Project Design Philosophy

Dowdens Pumping & Water Treatment’s Rockhampton branches design philosophy for this project was:

Cost-Effectiveness
Innovation
Ease of Installation
Simple & Reliable Pump Operation
System Reliability & Reduced Ongoing Maintenance.

The Grundfos RSI Solar Pumping System was designed, manufactured, installed and commissioned on time and within budget.