IN Papua New Guinea a mining exploration company, upon meeting the statutory requirements, is issued with the special mining lease licence and environmental permit by the relevant state agencies and departments.
When exploration is completed, as well as a feasibility study for mine infrastructure development, facilities are constructed.
Appropriate mining plans and methods, containing mine wastes treatment and disposal plans are signed and approved.
Construction of mine infrastructure and facilities commences. The developer constructs roads, airstrips, bridges, camp sites, waste dams, hydro dams, tunnels and so forth.
Community service assistance to schools, health centre etc may be provided by the developer before mining commences.
Relocation of people will take place if villages are situated near the mining area. The company will build new villages.
Mining commences within the approved special mining lease perimeter. If one party is left out, the process is put on hold.
Mine wastes come in many forms depending on the mining method applied as well as the style of economic mineralisation within the subsurface.
Both open cut and underground mining methods generate significant amounts of waste.
Mine wastes may come from overburden materials that are dug out to access the economic minerals.
Also, after the rocks containing the minerals have been ground and processed to extract the minerals and metals, they create another form of waste.
Slag is another type of waste taken out from the mine mill, which can be remoulded and re-modified to suit road construction-sealing purposes.
In the case of the Frieda River Project, where copper, gold and silver will be mined, there may be a possibility to turn the mine waste into industrial products.
Waste rock units coming from within the mine area may possess mineral characteristics that allow it to be turned into eco-friendly bricks.
A study on brick production at a copper mine through the geopolymerisation method has been carried out by Saeed and Zhang under the Department of Civil Engineering and Mechanics at the University of Arizona in the USA.
If this method is proven to be viable it could be applicable in the Frieda River Project.
The procedure for producing the bricks simply includes mixing the tailings with an alkaline solution, forming the brick by compressing the mixture within a mould under a specified pressure, and curing the brick at a slightly elevated temperature.
Two main mineral species required to produce geopolymerised bricks are silica and alumina which are usually in abundance.
The main factors for this technology to work are high temperatures and pressures and alkali solutions. Kiln firing for brick production using mine tailings has significant environmental and ecological benefits.
Now would be a good time for the developers of the Frieda River Project to look into these processes to see if they could be used to lower the waste levels by converting the waste into a useful building product.
Robson Urai is a young Sepik geologist studying in New Zealand. One of his interests is in the conversion of mine waste in to useful products. He has provided the technical papers below for people who wish to know more about the technology