Our article in the October 2024 issue of North American Mining, titled “How Valve Solutions Improve Tailings Disposal and Water Management,” is the second installment in a two-part series explaining how innovative valve solutions can be used to improve mining operations. Part two focuses on tailings disposal and water management/chemical makeup.
Contending with dewatered tailings
As part of their conservation efforts, mines are removing increasing amounts of water from tailings slurries, making the slurry thicker and more difficult to transport. This creates significant pressures at the front end of disposal piping systems, with valves in these locations often requiring 300# flange ratings.
The best valves for this service are full-ported, severe service knife gate valves, such as the Clarkson KS3 ASME Class 300. As pressures fall further in the tailings network, Clarkson KS1 ASME Class 150 Severe Service Knife Gate Valves with 150# flange ratings are capable and cost-effective.
Emerson’s Clarkson KS1 (left and middle) valve carries a full 150# flange rating, while the severe service Clarkson KS3 (right) carries a 300# flange rating. Both valves are reversible, have rotatable wear rings, and have advanced seals for excellent shutoff
Valves for water management and chemical makeup
Mining operations necessitate a variety of processes involving utilities, water management, and chemical makeup, with each requiring automated isolation valves.
Basic water management can be handled using butterfly valves with stainless disks and EPDM seats, such as the Keystone Series GR Butterfly Valve. Chemical makeup valves usually involve more corrosive chemicals, such as caustic or sulfuric acid. In these cases, a resilient seated butterfly valve with PTFE lined body and disc, such as the Keystone Figure 990 Butterfly Valve, is a better choice.
The Keystone Series GRF offers PTFE-lined butterfly valves spanning line sizes from 2-72 inches, making them a good choice for the large line sizes common in tailings water recovery.
Emerson’s Keystone GR butterfly valve (left) works well for basic water processes. The Keystone F990 (middle) is well suited for chemical makeup and corrosive applications, and the Keystone GRF (right) comes in line sizes up to 72” for tailings water recovery applications.
These applications often include chemical tanks that may require nitrogen blanketing and overpressure protection, with the goal of protecting the tank, while minimizing nitrogen usage and emissions. Fisher nitrogen blanketing regulators and Enardo Enhanced Sealing High-Performance Vent-to-Atmosphere Pressure/Vacuum Relief Valves are effective choices for these applications.
Electric actuator advantages
While electric actuators were once relatively uncommon due to torque limitations and lower electric power availability, technological advances have greatly increased their viability. Advanced electric actuators, such as the Bettis RTS and XTE3000, are especially useful in remote tank applications and tailings networks because their embedded control and communication options enable remote control and monitoring.
Advances in electric actuator torque, efficiency, and remote monitoring have altered the economic landscape driving valve actuation selection in mining applications.
Advanced actuator solves remote tank challenge
One mine using water trucks for dust control sought to reduce travel distance to refill the trucks. To do so, the mine needed a way to fill a remote tank a mile away from the main water supply lines. The tank was fitted with a local level transmitter wired to a Bettis RTS actuator.
The actuator controls a Keystone K-LOK High Performance Butterfly Valve at the tank inlet that opens when the level is low and closes when it is high.
Next generation, non-intrusive electric actuators (Emerson’s Bettis XTE3000 Electric Actuator shown on left) provide SIL 2 reliability as standard, and up to SIL 3 reliability, in a double channel configuration with programmable stroke profiles and advanced diagnostics. Motorized actuator designs (Bettis RTS Series actuator shown on right) can fail open or closed on loss of power using a mechanical fail-safe design with spring, and they can also provide SIL 3 reliability
At the other end of the tank supply line, a VFD regulates pressure to ensure that the water supply reaches the tank. This system keeps the tank filled without any control wires running from the process area to the tank.
Effective control solutions
Capable actuated valves, regulators, and relief valves can handle all the applications encountered in most mines, including tailings disposal and water management/chemical makeup applications.
Proper equipment selection requires a complete understanding of the difficulties associated with each unit operation, as well as knowledge of the numerous equipment options available to satisfy those needs. Emerson has extensive experience in a wide range of mining applications worldwide, and it offers a broad selection of control solutions to help mines meet their specific requirements.
Visit the Control Valves section on Emerson.com to know how you can meet your process reliability and performance goals by bringing intelligence to your entire valve assembly.
