Mining uses compressed air for pneumatic tools, hoists, pumps, controls and actuators, according to the US Department of Energy, and gold plants need dissolved oxygen in the cyanide leach, where oxygen is typically the rate-limiting reactant (Eriez, 2020). Ultra Controlo supplies the ULTRAOX VSA oxygen plant, whose datasheet lists gold leaching in mines.
The US Department of Energy (2016) lists compressed air uses in mining; Eriez (2020), K. E. Haque (1992), the US EPA (1994) and an SME paper (1996) describe the uses of oxygen and air in gold processing.
Air-powered tools, which the DOE notes generally cost 7 to 8 times more energy than electric tools for the same mechanical output.
Hoists, pumps, controls and actuators, listed by the DOE as example uses of compressed air in mining.
Gold dissolves only when both oxygen and cyanide are present; with cyanide typically in excess, oxygen is the rate-limiting reactant, so leach tanks are sparged with air, oxygen-enriched air or high-purity oxygen (Eriez).
Pre-aerating the slurry with air or oxygen alleviates the effects of soluble sulphides, arsenates and antimonates on cyanidation (Haque, 1992).
The reaction of the cyanide solution with free gold is oxygen-dependent, so the solution is oxygenated before application or during spraying (US EPA, 1994).
Heap biooxidation of refractory ore needs large amounts of oxygen, supplied by natural convection, diffusion from the surface or forced air ventilation (SME, 1996).
Sources: US DOE and Compressed Air Challenge, Improving Compressed Air System Performance (2016), p. 16 and Table 1.2; Eriez, Gold Leach Tank Aeration (Austmine, 2020); K. E. Haque, CIM (1992); US EPA, EPA 530-R-94-013 (1994); R. W. Bartlett, SME (1996).
Published sources on gold leaching describe how the gas is chosen. The figures below describe one ore and one plant.
Air can only give so much dissolved oxygen; beyond that, the oxygen partial pressure has to be raised by enriching the air or using pure oxygen. Oxygen costs more than air, but Eriez says the metallurgical gains more often than not offset the cost.
Source: Eriez, via Austmine (2020).
Extracting 94% of the gold took 1 g/L of sodium cyanide and a 48-hour leach at 7 ppm dissolved oxygen, but 0.25 g/L and 16 hours at 20 ppm, with a coarser grind.
Source: M. Wong, CIM (1995).
Two PSA oxygen generators supply about 8 tons of oxygen a day at 92% purity to one mine's CIL tanks, with an average of about 24 ppm dissolved oxygen in the first two leach tanks.
Source: Cyanide Code recertification audit (March 2019).
ULTRAOX VSA delivers 75% to 95% oxygen at 50 kPa; its datasheet lists gold leaching in mines. Sources: as noted; ULTRAOX VSA datasheet.
The oxygen plant whose datasheet lists gold leaching in mines, and general lines that the Ultra Controlo Industrial 2026 catalogue offers for any industry.
75% to 95% oxygen at 50 kPa, with an additional oxygen booster on demand, on a skid or in a container; the datasheet lists gold leaching in mines.
ULTRAOX VSAOil-injected rotary screw compressors in fixed speed, variable speed and two-stage versions, designed and built by Ultra Controlo for any industry.
Industrial overviewPreventive and corrective maintenance, original spare parts and emergency support for Ultra Controlo equipment and partner brands, anywhere in the world.
Technical assistanceSources: ULTRAOX VSA datasheet, pp. 2 and 3; ULTRASCREW datasheet; Ultra Controlo Industrial 2026 catalogue, pp. 8, 9, 16 and 22.
Ultra Controlo is a Portuguese manufacturer of compressed air, vacuum and technical gas systems, with 40 years of experience. We design, assemble and test our own compressors, dryers and carbon towers in Portugal, and supply and service five partner brands.
ULTRASCREW compressors, ULTRASEC and ULTRADRY dryers and ULTRAK activated carbon towers.
Gardner Denver, Elmo Rietschle, Thomas, Speck Pumpen (Circutec) and Speck Triplex.
Preventive and corrective maintenance, original spare parts and emergency support, by our own team.
Source: Ultra Controlo Industrial 2026 catalogue, pp. 3, 10, 16, 17 and 22.
The US Department of Energy sourcebook (2016) lists pneumatic tools, hoists, pumps, controls and actuators as example uses of compressed air in mining, and notes that air tools generally cost 7 to 8 times more energy than electric tools.
Eriez (2020) notes that the gold-cyanide reaction needs both oxygen and cyanide; with cyanide typically in excess, oxygen is the rate-limiting reactant, so leach tanks are sparged with air, oxygen-enriched air or high-purity oxygen.
Published figures vary: one gold mine's 2019 Cyanide Code audit records an average of about 24 ppm in its first two leach tanks, and a 1995 study of one ore compared leaching at 7 and 20 ppm.
WHO (2023) says VSA operation is less affected by altitude, and PATH and CHAI (2021) say VSA plants can operate at higher altitudes without a reduction in performance; both documents were written for medical oxygen plants.
Its datasheet states that ULTRAOX VSA can replace existing cryogenic systems with liquid oxygen tanks or work as the main source of supply, delivering 75% to 95% oxygen at 50 kPa.
The ore and the leach circuit, the oxygen you use today, the altitude and the power available. We reply with the equipment that fits.
