Sand dams are the most common tailings storage facility and are made by splitting whole mill tails, typically 25 to 30% solids, into coarse and fine material using cyclones. The coarse material, potentially with waste rock, is used to build the walls of the dam. The fine material is pumped into the containment area and allowed to settle.

Advantages

• Low capital cost
• Low operating costs
• Suitable for a wide range of mining applications and volumes.

Our technology solutions

KREBS® gMAX® cyclones incorporate performance-enhancing improvements to the inlet head, cylinder section, cones and apex to optimise cyclone performance by minimising turbulence while maximising tangential velocity. Benefits include: finer, sharper separations at high capacities; fewer cyclones required for optimal performance; extension of liner wear life; and the ability to retrofit into existing installations.

SmartCyclone® is our monitoring and control solution that reduces cyclone-related process issues, improves cyclone overflow particle size distribution, and predicts and controls maintenance schedules. Benefits include: stabilised cyclone operation; continuous wear monitoring and management; predictable cyclone circuit maintenance; and increased production capacity: the process can be operated closer to the limits of the cyclone manifold design.

KREBS® slurryMAX® pump range includes proven features such as an adjustable wear ring that closes the suction side impeller clearance between the suction liner and the eye of the impeller. This reduces hydraulic recirculation and helps maintain the design fl ow over the life of the pump, increasing the life of the impeller. Benefits include: even and predictable wear life; interchangeable material options; energy savings; and elimination of gland water requirements.

Our thickened tailings solution uses a high-rate or high-density thickener, resulting in 50 to 65% solids, to recover water in tailings prior to disposal. With this option, you will recover higher volumes of water and reduce losses to seepage and evaporation.

Advantages

• Higher water reclamation for re-use
• Reduced chance of seepage and evaporation.
  
  

Our technology solution

Derived from Dorr-Oliver® and EIMCO® technologies, our thickening equipment includes bridge-supported and column-supported designs to suit both smaller and larger throughput mines. Tanks can be in-ground, on-ground or elevated. High-rate thickeners are designed to provide roughly 12 times the throughput of conventional machines of similar size. This means: maximum capacity, improved control, increased underflow density and lower flocculant dose.

Technical requirements

Requires large-volume thickening technology that incorporates optimised feedwell design and feed slurry dilution methods. Energy dissipation and solids distribution need to be evaluated and feed-dilution systems should maximise flocculation efficiency and settling rates.

Tailings produced from our paste and/or filter tailings system can also be stored underground in previously worked-out voids. The tailings are dewatered and pumped below ground. The paste is often mixed with a binder, such as cement, to provide support to prevent heading collapse and subsidence issues. Any excess paste tailings can be transported to the surface tailings storage facility.

Advantages

• Minimal surface disturbance – reduced footprint, dust generation, visual impact and surface water contamination
• Backfill provides support to the underground workings, including reduced risk of rock bursts
• Binders help minimise groundwater contamination
• Reduced acid rock drainage (ARD) for certain ores
• Allows for previously unmined ore (pillars and supports) to be extracted

Our technology solution

Our filtered tailings solution, often referred to as dry stack tailings, uses high-rate or high-density thickener followed by a variety of filters, resulting in 75 to 85% solids, to recover water in tailings prior to disposal.

Advantages

• Water reclamation and makeup water minimisation reduces costs
• Minimised tailings management facility (TMF) area – footprint can be less than 50% of a conventional TSF
• Reduction in closure costs at end of mine life – progressive closure possible
• Reduced tailings risk improves safety
• Suited to areas of high seismic activity.

Our technology solution

The trend in the industry is towards filtered tailings. Filtered tailings increase the amount of water returned to the plant for reuse, as well as decreasing the amount of water lost to evaporation and seepage. There are numerous advantages including: Lower maintenance costs and higher performance; easy operation and maintenance accessibility; reliability of a proven, high-performance design; availability of process control and DCS communication; and a range of reliable dewatering equipment, including vacuum filters, pressure filters and centrifuges.

Technical challenges

Selecting the correct filter for the tailings is critical. Some tailings can be sufficiently dewatered using a vacuum filter while other, more difficult tailings, require pressure filtration. The geotechnical properties of the stacked tailings will drive to what degree the tailings must be filtered. The material handling system, conveyors and stackers, must be designed to match the quality of the filter cake produced. Designing a filtered tailings solution that is effective, but not capital or operating cost prohibitive, is required.

We developed our co-mingling solution, named EcoTails®, in cooperation with Goldcorp. EcoTails blends “fast filtered” tailings with waste rock in transit and creates a geotechnically stable product called GeoWaste™. When blended properly, GeoWaste is easy to convey and has a high strength when stacked. EcoTails and GeoWaste make dry stacking possible for large scale mining, even in areas with high seismic activity.

Advantages

• EcoTails carries all the advantages of filtered tailings and delivers the following added bonuses:
• Tailings fill the void space between rock particles reducing the opportunity for oxygen flow
• Reduced acid rock drainage (ARD) potential
• Coarse waste rock particles provide shear strength for improved physical stability
• Even smaller total waste footprint - achieved by combining both tailings and waste rock.

Our technology solutions

Our fast filtering technology increases the speed of the filter process allowing greater volumes of tailings to be handled in a shorter time. Through this system, filter cakes with high moisture content are co-mingled with waste rock to provide the needed geotechnical strength for stacking.

Fixed and semi-mobile crushing stations configured to process your waste rock for efficient co-mingling.

BulkExpert™ is our unique solution that focusses on unmanned and optimised operation of dry stacking equipment; lowering cost per tonnes, reducing equipment wear, saving energy and increasing safety.