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Sensor-based ore sorting transforms the bottom line in gold mining

Exploring gold ores becomes more challenging every year. Mines increasingly deliver lower grades and complex mineralogy, forcing mills to process more material and thus compounding the expanding ratio between these tonnages and the ounces of ore produced.

Gold

20-40mm // Input // COM Secondary XRT

INCREASE PRODUCTIVITY WHILE REDUCING  ENVIRONMENTAL IMPACT

It is clear that pre-concentration with sensor-based sorting provides a number of bottom-line benefits to users including increasing cash values per tonne, reducing environmental impact in terms of resource inputs (energy, water, wear and tear of equipment, process reagents…) as well as reductions in the volume of tailings produced.

Sensor-based ore sorting can be used to significantly upgrade ROM ores prior to feeding them to the concentrator. With less barren material being treated, there is a knock-on effect which produces further savings in a range of ancillary mining activities from haulage costs through to a reduced tailings footprint. All these factors contribute to a lower mining cost per tonne. The primary aim is to increase mine recovery by reducing the cut-off grade and processing the extra material without compromising current mine production. This creates new mill capacity by rejecting waste material without significant capital expenditure.

Adopting sensor-based ore sorting technology promotes a pre-concentration of ore in the early stages of the production process. This pre-concentration is achieved by deploying X-ray-transmission (XRT) and/or LASER sensor analysis to identify viable material alongside an air ejection process to separate the ore from sub-economic waste.

DUAL-PHASE SENSOR-BASED ORE SORTING FOR EVEN BETTER RESULTS

Gold ores are typically amenable to sensor-based ore sorting to some degree, and this is usually accomplished with XRT or laser sensors, or a combination of both. A two-step sorting flow-sheet consisting of an XRT rougher plus a laser scavenger (or alternatively, a laser rougher and an XRT scavenger) has already proved an optimal recovery method for a number of deposits. In quartz-type gold deposits, as well as purely with the quartz itself, the gold can also be associated with pyrites both within the quartz vein and outside (the alteration halo effect) – albeit often in lower concentrations. Ore recovery of over 90% and mass removal of 30 – 60% has been regularly experienced using these two-step particle sorting flow-sheets.

PROJECT DEVELOPMENT AND TESTING FOR GOLD 

Experience of applying sensor-based ore sorting in several mines has proved how critical/important the geological approach is to investigating and understanding the sorting feasibility of complex ores, and gold ore in particular. This is because, although the focus is not on gold detection itself, the correlations between detectable characteristics and gold content need to be present, well-understood and reliable in order to discern how gold deportation into product and waste fractions can best be achieved.

Metal production from existing operations can be increased, while previously uneconomic deposits and low-grade stockpiles may also become viable. Contact us today so our experts can help you asses how sensor-based sorting can boost and optimize your gold recovery process. To take advantage of our gold processing expertise, just schedule an analysis at one of our test centers.