Mining industry

As global population grows, urbanization and industrialization processes assume massive proportions (particularly in emerging economies), resulting in stronger demand for different types of commodities, including those produced by the mining and metal processing industries.
Despite the dramatic increase in recycling, an overall need in newly mined materials rises constantly.
Since the world’s metallic deposits discovery rates decrease (and so do the grades of metals in the newly researched deposits), most productivity increases can be achieved through the ability to process lower-grade ores using more efficient and cost-effective technologies.

Heap leaching

After mining, crushing and sometimes grinding, the ore is placed on a lined pad (a base) in a heap. The material is then irrigated with an appropriate lixiviant such as cyanide or acids to dissolve out the metal required.
The leachate is collected in so-called pregnant leach solution (PLS) ponds.
During the PLS processing, some by-products can be generated. These have to be appropriately stored.
The raffinate (i.e. liquid that remains after the components required were extracted from the PLS) goes to barren solution ponds designed for a temporary containment of processed pregnant solutions.

For extraction of metals such as gold, copper, nickel, zinc and uranium, the heap leaching technology has been experiencing a sustained growth over the last decades.

Traditional mineral processing methods

These methods also very often require grinding the ore into fine particles to facilitate extraction of the target element(s). Materials left over after the process of separating the valuable fraction from an ore are called tailings. The tailings very often contain dangerous substances and therefore the areas where the materials are to be stored have to be made environmentally safe (which was not always the case during early mining operations).

When the storage capacity of the disposal site (settlement pond) is fully used up, closure phase of the tailings impoundment is to be performed and the storage areas restored to a natural-like condition.

Tailings come into existence during the production processes of e.g. aluminium, gold, zinc, lead, silver, copper and other strategically important metals. As the tailings can contain significant residual quantities of different minerals, they might be utilized as low-grade ores sometime in the future.

Shale gas

Given the low porosity of oil shale, traditional methods are not suitable for shale gas extraction. Shale gas mining is thus carried out using the method of hydraulic fracturing (hydrofracking). Water with an admixture of sand (or other incompressible particles) and various chemicals is being pressure-pumped through wells into sedimentary rocks hundreds of meters beneath the surface. Pressure water opens cracks in shale formations, thereby disrupting the rock and creating a system of irregular ducts; the particles transported by water hold the ducts open until the shale gas flowing through them has been extracted from the rock.

The very denomination of this method suggests that the most important material used in hydrofracking is water; the volumes consumed during the process are enormous. For that reason, shale gas mining areas must be equipped with large water reservoirs; it is required that these are lined with a reliable and long-lasting material. The same applies to the ponds where the water returning from the wells is being kept. It must, however, pass through a cleaning procedure removing all harmful substances and impurities before being re-used.

Interesting projects

RESIDUE DISPOSAL SITE AUGHINISH ALUMINA

Product(s):	JUNIFOL PEHD
Location:	Aughinish, Ireland
Installation:	2010-2011

TALVIVAARA HEAP LEACH PADS

Product(s):	JUNIFOL PEHD 2,0 G/G
Location:	Sotkamo, Finland
Installation:	2011