Mine Dewatering System Design Validated Using AFT Fathom
AFT Fathom™ Case Study
Blenray | Mine Dewatering System | Mining & Metals
“The AFT Fathom software quickly enabled what-if scenarios to be
modeled to determine compliance with the design criteria. The model
could be provided to an international customer who could run the model
using the AFT Fathom viewer.”
– Geoffrey Stone, Principal, Blenray
PROBLEM
- Modification of mine dewatering system
- Special attention to pump NPSH margin, to accommodate the large pressure drop from unusually small pipes
ANALYSIS
- AFT Fathom was used to model different pump and system configurations
- Pump VFD features allowed the engineers to meet suction and discharge pressure control criteria
SOLUTION
- System was designed to allow for frequent reconfiguration as needed by the client
- Years of successful operation
Ready to try AFT Fathom?
Problem Explained
Geoffrey Stone, principal at Blenray Pty Ltd, used AFT Fathom to model a proposed modification to a mine dewatering system in Indonesia. The proposed system consisted of four skid-mounted parallel pump sets, lined up in series, and fed from an existing pontoon pump system.
The system required a flow capacity of 480L/s (7,600 gpm), over a pipeline distance of 4,300 meters (14,107 ft), and an elevation gain of 400 meters (1,300 ft). Maintaining an appropriate pump NPSH margin, while using relatively small pipes, was critical to the success of the project.
Tools & Analysis
The smaller than usual pipes and skid-mounted pump sets were required to accommodate frequent reconfiguring of the pumping system. Criteria:
- PE100 pipe material, due to pH< 3
- Pipe diameter of DN630
- High chrome bodied slurry pump to handle particles up to 3mm • Minimum 10m head available at all times to meet the NPSH requirements of the pump
- Discharge pressure not to exceed 10bar
- The location of the pump sets not uniform AFT Fathom calculations were used to validate multiple pipeline configurations and aid in the control system development.
Solutions & Benefits
The system was modeled in steady state using existing and selected pumps as well as actual pump curves to ensure that a specific pump was met. Pump speeds could be changed in the model to meet the control criteria of suction and discharge pressure and pump NPSHa within the design rating of the PE100.
Hydraulic power was examined and compared to the performance of the diesel unit’s capability driving the pumps. The reduced speed, elevation and constant operation of the diesel motors was a challenge with some pump set locations. This was considered in the pump set selection and placement along the mine haul road. The PE100 properties were contained in an AFT Fathom user-generated database using criteria from Australian Standard AS 4130. This enabled the selection of various classes before the PN12.5 was chosen. The model allowed the implementation of a cost-effective solution using materials and equipment that the operators were familiar with.
AFT Fathom benchmark results and measured control
valve position data for heater gravity drain system
HGL & Elevation vs. Flow Length