1. Pumps for mining: mineral slurry versus peripheral water
Understanding the boundary between slurry pump and water pump is the starting point for any correct mining specification. Slurry pumps serve fluids with high abrasive solids content in suspension: mill discharge, flotation pulp, high-density thickener underflow, tailings pumped to disposal.
What characterizes slurry is the combination of solids content, particle hardness and size and mixture density — data that come from the process characterization of each plant, not from a generic range.
The FBCN is a process centrifugal pump with a radial single-suction impeller and wear ring (MTEC-03/00, item 2.2), indicated for clean or turbid liquids; the manual asks for FB consultation for fluids with suspended solids (item 2.3). In abrasive slurry, impeller, wear rings and casing wear quickly — that is why this service falls outside the series application, and FB publishes no service life for it.
Slurry pumps may use linings, alloys and passages designed for the process abrasion and solids. That construction is not established in the reviewed FB catalogues. FBCN drawings and materials must not be used as proof of suitability for mill discharge or concentrated tailings.
Warning
Practical criterion: if the fluid is process slurry (mill discharge, flotation, underflow, tailings), the service belongs to a slurry pump. If it is clarified water or drainage with fine sediment, the FBCN is assessed with the solids analysis — content, hardness and size —, and FB confirms whether the application fits the series.
2. Mine drainage pumps: hydraulics, infiltration and acid pH
A mine drainage design must identify water inflows, permissible levels and site-specific rainfall and infiltration scenarios. Continuous flow, storage volume and contingency capacity follow that balance; not every mine has the same duty or requires continuous pumping.
In a deep underground mine, drainage may involve several cascading pumping levels, with flows that accumulate from level to level — each level receives drainage from the next plus local infiltration, and pumps upward.
Measure composition, pH, sulphates, chlorides, temperature and solids, as well as head per level. FBCN documents cast iron, WCB and CF8M; pH alone does not approve any material. FBCN publishes up to 135 m, and FBME up to 300 m and 400 m³/h as independent maxima. Consult FB about solids before selection; S2/S3 are sealing arrangements, not approval for any abrasive water. For pumps in series, check suction and total pressure at each assembly.
In a cascade, each station works within its model’s range. The FBCN manual limits flow to between 0.1 and 1.1 times the best-efficiency flow (Qot) on bearing frames 30 and 40, and between 0.15 and 1.1 Qot from frame 50 upward, with up to 10 bar at suction (MTEC-03/00, Table 1). On the FBME, minimum flow is 0.2 of the optimum flow, suction accepts 10 bar and discharge 30 bar at zero flow (MTEC-08/01, Table 1).
A sump that fills and empties shifts the operating point along the cycle; level control and start/stop logic must keep each pump within that range.
The FBCN’s back-pull-out construction lets the bearing assembly be removed from the volute without disconnecting or misaligning the piping, which the manual links to easier assembly, disassembly and maintenance (MTEC-03/00, p.1). The drive can be an electric motor or a diesel engine (item 5); the choice, like pump redundancy, comes from the mine’s contingency plan.
The wear parts are identified in the manual: the casing has a wear ring on the suction side and the impeller one on the pressure side, except on sizes 25-150, 32-125 and 32-125.1 (items 2.1 and 2.2). These are the clearances to measure at drainage stops.
3. Process and recirculation water: the flotation water circuit
Flotation beneficiation plants consume large volumes of water, largely recirculated from thickeners and dams. The plant water balance defines flows and pressures at each point.
Most of these points handle clarified water — the FBCN field. What changes from point to point is the solids content escaping clarification and the chemistry of recirculated water, which accumulates reagents and salts; both come from the analysis.
The main water points in the beneficiation plant are: (1) intake of recovered water from the dam or settling basin; (2) process water for conditioning and flotation; (3) clarified tailings water recirculated to the process; (4) washing and spray water — when the required pressure exceeds the FBCN envelope (135 m, about 13 bar in water), the FBME, with up to 300 m, or another technology is assessed; and (5) sealing and cooling water for process equipment such as mills and crushers.
At every point, solids and chemistry are confirmed in the analysis before selection.
The pump itself enters that balance when its sealing uses external water. With packing, the FBCN manual indicates about 1 l/min of sealing liquid for arrangements S1 and S2 and about 3 to 5 l/min of flushing for S3, always from an external source and up to 105 °C (MTEC-03/00, Table 1 and item 10). Added pump by pump, that flow goes into the sealing water network of point (5).
4. Tailings dam: what is FB and what is not
After the Mariana (2015) and Brumadinho (2019) failures, Law 14,066/2020 amended the National Dam Safety Policy (Law 12,334/2010) and prohibited building or raising mining dams by the upstream method, requiring the decharacterization of existing ones within a deadline the regulator may extend for technical unfeasibility. Regulation and inspection of the activity lie with ANM, together with environmental licensing.
From a pumping standpoint, a conventional dam has three distinct lines: tailings discharge (slurry, dedicated slurry pump territory); clarified water recovery from the pond (water, FBCN field); and controlled dewatering of the reservoir for maintenance or decharacterization, whose flows and levels come from the approved plan for the structure.
FB serves clarified water recovery and dewatering with FBCN in the material indicated by the analysis — cast iron, WCB carbon steel or CF8M stainless. In floating installations, the design of the pontoon, mooring, flexible piping and power supply belongs to the mine engineering or the integrator; FB supplies the pump or motor-pump set for the operating point and checks NPSH against the pond level variation and the suction position.
5. Materials and corrosion/abrasion challenges in mining
Even in "clean" beneficiation water, material and sealing depend on chemistry and sediment. The documented FBCN casing materials are cast iron, WCB carbon steel and CF8M stainless (MTEC-03/00); the choice comes from the water analysis — pH, sulfates, chlorides, dissolved metal ions — and from the operation’s corrosion history.
For acid drainage, check complete composition, concentration and temperature against corrosion data and operating inspections. CF8M does not resist every acid or mixture. If documented options are unsuitable, confirm feasibility and availability of another construction before specifying a special alloy.
Alkaline water — circuits with caustic soda, as in alumina refining — has its own temperature and alkalinity; the material comes from the corrosion table for the real condition, not from a general rule.
Abrasion: fine sediment wears the impeller and wear rings over time. FBCN manual criteria: S2 or S3 sealing arrangement for particles; peripheral speed limited by impeller material (40 m/s in cast iron, 60 m/s in ductile iron or carbon steel, 80 m/s in stainless — item 6); and lower speed reduces particle velocity — a 250 mm impeller runs at about 22.9 m/s at 1,750 rpm, against 45.8 m/s at 3,500 rpm.
FB publishes no service-life gain for these measures; the effect is measured in the operation history.
Table 1 of the FBCN manual provides a 3.3 mm corrosion allowance, which does not replace choosing the material from the analysis. Maximum speed also changes with size: 3,500 rpm on bearing frames 30 and 40, as on the 80-250, and 1,750 rpm from frame 50 upward, as on the 100-315 and 150-400 — on those sizes, the lower speed against abrasion is already the table limit.
6. Brazilian mineral sector context
Mining in Brazil is regulated and inspected by ANM (National Mining Agency), with federal (Ibama) or state environmental licensing, and dam safety follows Law 12,334/2010, as amended by Law 14,066/2020. For pump specification, this translates into traceable supply documentation and maintenance plans the operation can demonstrate.
In the main process, slurry pumps are the core equipment; in the water periphery, FB supplies FBCN and, for higher heads, FBME, manufactured in Cabreúva-SP with CNC machining, assembly and a performance test bench conforming to ANSI/HI 14.6, the test standard for rotodynamic pumps such as both series. A certified curve and FAT are included when they are part of the contracted scope. FBFS fire-fighting sets follow a design per NFPA 20 or ABNT NBR 16704 when specified.
Documentation, tests, lead time and parts availability are defined in each proposal; FB does not compare lead times with imported suppliers or publish a list of customers in the sector.
To quote a pump for mining, describe each point separately: water source (drainage, recovered water, process or sealing water); solids content, hardness and size; pH, sulphates and chlorides; temperature; flow and head with the suction conditions; operating duty and available drive. With these data, FB confirms whether the point fits the FBCN or the FBME, in which material and sealing arrangement — or states that the duty belongs to a slurry pump.