Application Of Lasers In Mining
In present industry, mechanical drills are used to remove earth materials and they are time consuming as well as inefficient when compared to lasers which can do the same task when supplied with high amounts of power in the range of kw. Also it is easier to change the laser’s power density based on requirement without having to replace the mechanical drills. The laser can be delivered close to the surface or away from it with the help of fiber optic cables which can transmit the laser with high accuracy and precision within a 1km range.
There is still need for development in this field. Introduction: The recent rise in the interest for constructing tunnels has risen from The Boring Company and the Hyperloop owned by Elon musk. They are building a network of roads underground, down below the cities they live. Boring is a tedious process that would take anywhere from several months to years. It is not an easy task to dig out tonnes and tonnes of earth material. At present the drills that are used to bore tunnels use mechanical drills which can wear out over time. Moreover the composition of the rocks varies at different locations and hence we will have to change the drillers accordingly. Eventually it is time consuming. Suppose we use larger mechanical drills, their source of power would generally be diesels(fossil fuels). And in some cases electricity is used but still not all components are designed to be electric powered. To dig out the rocks, it is not possible to blow up using explosives if we are trying to eliminate the use of mechanical drills, simply because we won’t be able to get a desired shape of the tunnel and could also cause a collapse of the surface.
Proposed Work: An efficient alternative that we propose is the use of high energy lasers to dig out the rocks. Lasers don’t use fossil fuels, rather it uses electricity which is environment friendly considering the rise in the consumption of solar energy enabled by the advancements in the storage technology like the gigafactory, powerwall and solar city by Tesla. But a single laser cannot be used to carve out an entire tunnel because it would then require an immense amount of power and such large amounts of power can cause the rocks to melt, the worst case being the hot plasma caused during the operational period can cause the laser source to malfunction or get destroyed completely from the excessive heat.
So 2 instead we will be using multiple laser sources whose combined power would weaken the rock wall and eventually it would break. It is generally faster and efficient compared to the traditional method. We can have a protruding source placed on the machine or a better option is to use fiber optic cables that are capable of transmitting such energy laser. Any kind of possible error could result in a havoc as the work environment itself is hazardous. So the cables must have high precision and no openings so that the laser doesn’t escape at an undesired exit. When fiber optics are used the need for contact with surface can be eliminated. If no contact is made and there are no mechanical parts then there is no possibility for wear of the components unlike in the case of mechanical drills. Also with the help of lasers we can get the tunnel to have our desired shape, its all just the positioning of the laser source.
As we can see in the above image, the entire machine behind the drill would be the same. We will be just replacing the mechanical part with a set a laser beam sources. The smaller rocks would be collected at the bottom of the machine and sent through a conveyor within the machine, out of the tunnel. As the machine bores, the tunnel’s walls are placed simultaneously so that the upper surface holds off without collapsing.
The time consuming period in mechanical machines where we will have to change the drills when the machine encounters new materials, can be eliminated by just adjusting the power density of the laser accordingly. We will also need to have enough air supply so as to provide compressed air to the laser sources to remove the deposited dust. But this can be eliminated when we are delivering the laser beams using fiber optics from a certain distance so that the source isn’t placed close to the rock wall or make contact.
The laser beam cannot be from a single source due to the above mentioned reason. So we will be using multiple laser beams of less power to achieve the desired result. For the same reason of high temperatures the laser will be produced in the pulsed form instead of a continuous wave. Still the laser that will be used are of high energy having the capability of breaking rocks. So when the source isn’t fiber optics we will have to use a source that is made up of materials that can withstand very high amounts of heat without melting, similar to that used as heat shields in the space shuttles that act as a protective shield when entering a planet’s atmosphere(Eg. LI-900 silica made from pure quartz sand). .
Conclusion: Laser’s application in this field is still in its initial stages and there is still lot of room for research and development. At present mechanical drills are preferred due to certain fallbacks with the use of laser like huge amount of power supply requirement, need to keep the source, free of dust in a dust prone environment which is achieved with the help of compressed air supply blown over the source periodically. At a certain point of time all great inventions were considered impossible and just didn’t make sense to the people. But in the end there is always a way around the corner and nothing is impossible. The sole purpose of innovation is to overcome the obstacles and create the impossible. In a few years, there could be some research that would make use of the laser in a much better and new perspective in this field.
