A linear actuator for mining service should be sized from a calculated working load with a 1.5x to 2x safety factor, then derated against catalog force and duty-cycle numbers, not against marketing maximums [S2][S3].
The 2026 industrial catalog range for robust DC actuators now runs from 3,000N (linact-j3) up to 20,000N (linact-jl-01), with the workhorse 8,000N and 17,000N ratings dominating mining retrofits [S4].
Force rating and safety factor: how much headroom is real
Published guidance recommends sizing a 500 kg lift at 7,358 N (4,905 N x 1.5) and then selecting the next catalog step up, roughly 8,000 N [S2]. For dynamic loads, the pressure-velocity limit of a plastic nut can be exceeded before the static force rating, which forces a material change (bronze nut, ball nut) rather than a force increase [S3]. Static axial load, including shock, is the published ceiling, and on a lead-screw system with a plastic nut it is the gating limit well before the motor's stall force [S3].
The 10N = 1 kg rule of thumb remains a useful sanity check for screening, but it ignores the 25% to 35% duty cycle and -40°C to +65°C ambient derating, both of which are common on industrial mining models [S4][S5]. For a 1.7 ton (17,000 N) hood or chute lift, the LINACT-35 publishes exactly that force with an ACME or ball-screw option, but only 20% duty on ACME versus 35% on ball-screw, so the screw choice, not the force number, decides whether the actuator survives [S4].
Drive train: ACME lead screw vs ball screw in dust and shock
Lead screws are cheaper and tolerate side loads and contamination better, which is why they appear in most off-road and construction catalog models aimed at mining [S1][S4]. Ball screws give higher efficiency and longer life at higher duty cycles and can hold class C7 lead accuracy (~0.0003 in/in), with C5 tighter options on some sizes [S3]. For repeatable valve positioning, a ball-screw unit with selective-fit ball nut can cut backlash to 0.0002 in (5 microns) [S3].
For an 8,000 N retrofit on a haul-truck or feeder actuator, a DC permanent-magnet motor with an ACME screw is a common low-cost choice, but it is locked to 20% duty unless the OEM quotes the ball-screw variant at 35% [S4][S10]. The comparison below lines the three realistic options against mining-relevant criteria.
IP rating, temperature, and feedback: what is actually catalog vs custom
Standard catalog ingress protection on heavy-duty mining-style actuators is IP65 to IP66, with -40°C to +65°C operating temperature on units like the LINACT-BLK and LINACT-C [S4]. The LINACT-35 raises protection to IP66 and adds CE certification plus optional 0-20 mA or 0-5 V analog feedback, Hall sensor, magnetic switches, and end-stop signal [S4]. For real wash-down or slurry-exposed duty, IP66 is a defensible spec, but IP69K high-pressure, high-temperature cleaning is not on the standard data sheet and is treated as a project quote.
For a linear guide or linear module integrated actuator on a screening plant, four building blocks are required: a stable frame, a rotary-to-linear drive, a load-carrying linear guide, and a drive train, with a linear bearing specified for the radial load separate from the axial thrust rating [S9]. Position feedback is typically chosen as Hall, potentiometer, or encoder, with stroke adjustment via magnetic switches available as an option rather than a default [S4].
Duty cycle, speed, and life: the second number that breaks the unit
Duty cycle is the most common failure driver in mining retrofits: a 25% rating means 2 minutes on, 6 minutes off, while a 35% ball-screw rating allows 2.1 minutes on per 6-minute window [S4][S5]. Catalog speed for 12/24/36/48 Vdc DC units ranges from 3 mm/s to 102 mm/s at full load, with 5-23 mm/s typical for 17,000 N heavy-duty models, so a 500 mm stroke on the LINACT-35 takes 22-100 seconds end-to-end depending on load [S4].
Force and speed are inversely related on a fixed power motor, so a 17,000 N actuator at full load moves near 5 mm/s while a 3,500 N actuator can reach 102 mm/s [S2][S4]. Stepper-driven linear actuators generally need a 20-30% thrust margin over calculated load to keep heat down and life up, while DC PM models follow the 1.5-2x rule on static load [S2][S8]. Stroke length options for mining-grade units run from 50 mm to 1,000 mm as standard, with custom strokes available on industrial ranges [S4][S5].
Selection gates for a mining duty cycle
Engineers should lock seven numbers before quoting: working load, safety factor (1.5-2x for static, 20-30% margin for stepper), stroke, retracted and extended length, supply voltage (12/24/36/48 Vdc or 230/380 Vac), duty cycle, and IP rating, then choose the screw type and feedback option [S2][S5][S7]. For full-life applications on conveyor gates, dampers, and continuous indexing, an AC industrial unit is the safer default, while a DC PM ACME unit is the cheaper default for hood lifts, hatches, and infrequent damper drive [S5]. A robust linear actuator with IP66, 17,000 N, and adjustable magnetic switches is now a stock item in the heavy-duty mining segment, not a special build [S4].
For position-critical duties on screens and chutes, a linear encoder on the actuator rod, plus a closed-loop driver, gives the same kind of accuracy the screw geometry promises, while a mining dump truck hoist gate typically only needs end-of-stroke feedback [S3][S9]. Existing process engineers can also reuse the same sizing logic for adjacent material-handling picks, since ball screw selection for material handling follows identical load, lead, and life gates, and rail lubricant selection maps onto the same ambient and duty data.
Where catalog numbers stop and a quote begins
IP69K, ATEX/IECEx zone 1 or zone 2 intrinsic safety, stainless hardware, and 100% duty at 17,000 N+ are all outside the standard robust-actuator data sheet and should be treated as engineered specials [S4][S5]. Mining dust ingress, explosive atmosphere (methane or coal dust), and high-pressure wash-down each push the spec out of catalog and into a project review, even when the force and stroke numbers match.
Two trackable signals over the next quarter: published updates to the LINACT 2026 industrial data sheet covering IP69K options, and any ATEX/IECEx zone 1 mining-grade release from a heavy-duty DC actuator OEM, both of which would shift the standard force and duty numbers used in the gates above.