Imagine being able to remotely target and remove resources in deep wet collapsing environments with little to no impact on the environment.
If it sounds impossible it is because, up until now, it was.
In the past, minesites have had to remove overburden and topsoil in order to mine the riches that lay beneath the earth’s surface.
Land clearing has a terrible effect on the environment. And, in a world consumed by defeating the ugly beast that is climate change, every step taken to reduce adverse impacts on the environment is a crucial step.
One company has developed a product that has the ability to extract minerals from the earth’s seams while leaving the environment virtually untouched. The product/technology/equipment is said to revolutionise the way in which minerals are mined.
Over the past 10 years, SORD Resources Limited has worked with engineering Consultants to develop a ‘keyhole mining system’.
SORD Resources’ Director Neil Graham has described the invention as a big worm moving underground, sucking up all the minerals, pumping it up to the surface, processing it and dumping the waste back underground.
“What the world needs is to be able to access resources without the environmental cost of doing so — that is, without having to remove overburden, to drill, to blast or to crush and chemically process,” Graham told Australian Mining.
“Today, miners would like to be able to extract ore using minimum energy and virtually no exploration.”
According to Graham, the world has huge warehouses of wealth at its disposal that have been concentrated by mother-nature into layered alluvial deposits or lenticular beds such as a high grade strand line in mineral sands or a layer of iron sands, oil sands or a deep leads wash layer.
The SORD miner is designed to take out these alluvial deposits without disturbing the environment.
“The SORD miner does this at 5% to 10% of the energy, capital and operating costs of a conventional mine without anyone underground and without the 5 to 10 year mine establishment,” Graham said.
A joint effort
The SORD miner came about after early collaboration between many parties including the CSIRO.
CSIRO applied some mathematically modelling techniques to SORD Resources’ concept.
According to Graham, SORD Resources went to the CSIRO and asked it to model the various forces that might act on the SORD Miner to see if they were theoretically manageable.
The response from CSIRO’s Dr Julian Land, one of the project’s board members, was yes within certain constraints and assumptions, the SORD miner should deliver enough force to allow it to overcome drag to drive through the mining area.
To successfully develop the machine, however, a lot of ground work had to be completed.
The machine works by combining inertial navigation guidance systems with remote operation, control systems and a shield.
The shield is a square tube made from four sections of strong cloth material.
The material is drawn down from the surface then zipped together to form the tube at the SORD head and deployed behind the SORD miner.
The shield stays in-situ while the umbilical lines slide inside the water-filled inflated sheath.
A pressure of around 3 psi provided by a fluid head of a metre or more above the water table maintains the inflation of the Shield.
The SORD miner operates in a collapsing environment while using water jet cutters to create a slurrying activity at the front face of the head like a fluidised bed of ‘quicksand’.
It then transports the material using Warman Slurry Pumps to the surface.
It is projected that the delivery to the surface will be in the range of 200 to 10,000 tonnes per hour depending on the size of the slurry pumps used in the head.
Nominal production rates for alluvial resources are dependent upon the minerals to be mined but on average are approximately 2000 tonnes per hour of the target layer.
House of cards
The machine is currently being trialled at a Jandakot test site in Western Australia.
According to Graham, the machine has tested and demonstrated key technologies including the time system, shield deployment and re-deployment.
However, it has not just been smooth sailing for the team at SORD Resources.
Preliminary trials at the Jandakot test site resulted in track damage and slow progress.
The team was then forced to design a new type of track that would operate in continually in the collapsing, wet, fluidised environments.
“We were able to devise a hydrostatic water suspension track that allowed the SORD miner to float underground above a cushion of water trapped between the machine and the tracks,” Graham said.
“Through various tests and trials we came to the understanding that we needed to wear sneakers rather than cleats.
“In our first track design we kept creating point loads and water doesn’t like point loads, so we covered the entire track in 75 mm of ultra soft Liotex rubber. Now the SORD miner has virtually no resistance and no drag on the tracks,” he said.
The machine is said to float underground, extract the product, pump it to the surface via the Warman slurry pipes and leave the environment undisturbed.
Concerns have been raised about the stability of the earth once a machine is forced underground.
Like a house of cards waiting to fall, will the strata above the machine become unstable and collapse?
According to Graham, the most innovative aspect of the machine is its ability to pump the waste it extracts back into the earth.
“The SORD miner leaves no waste behind. All the waste fills the cavities, similar to the way the cavities are filled in an underground coal mine by paste fill,” he said.
“Honestly, the only major problem we have had with the SORD miner is a lack of funds.”
Due to the risk attached to the SORD miner and the current state of the economy, it is understandable that no major companies have come forward to finance the machine for a continuing period to date.
However, with a high likelihood of demonstrating each of the key systems and entering trial mining, there is the potential of opening the vast alluvial resources on the planet.
Based on trials completed to date, the minerals industry could soon see the SORD miner revolutionise the mining industry.