Quarrying and Sustainable Processes of Experimental Tunneling - Assignment Example

Excavation and sustainable operations of underground mining Name Institution Abstract Mining forms one of the best sectors that generate a lot of income for many nations across the world. This process has been carried out over many generations in time. Our forefathers also mined but they used crude forms and very crude methods that are in total contrast to the advanced mechanisms and methodologies of mining we have existing in the world today. There are two methods of mining; surface mining and underground mining. For purposes of this research and this report, the main focus will be upon underground mining. Underground mining involves the process of excavating beneath the earth’s surface to able to bring out minerals that have been lodged beneath this surface. Each mineral requires a certain specialized method of excavation following diversity in forms of value, depth, nature and form of the mineral. Some of these minerals are present in a solid rock state like gold and diamonds while others are in liquid form such as oil. This report will focus on the underground mining taking much into context the mining of diamonds as well as gold for the purpose of this study. Randomly sampled case studies will be used in this report to bring out the various parameters under scrutiny in a better format. However, despite this industry being among one of the best earners, it is also among one of the industries that bring about a lot of pollution to the environment. The impacts of this kind of mining on the environment will also be looked into keenly in this report and finally recommendations pertaining how the impact on environmental degradation could be mitigated given. Contents Abstract 2 Contents 4 Introduction 4 The process of excavation in underground mines 5 Safety of miners in the shaft excavation 7 Tools used in mining 9 Shaft mining as an environmental hazard 9 Case study: South Deep Twinshaft complex 10 Conclusion 10 Recommendations 11 References 12 Introduction Before the report embarks on the various aspects of the actual process of mining used in the underground, it is vital to understand in the preliminary stage how these miners make their way into the ground. There are several ways through which this is carried out and as outlined in the abstract section of this report, the method depends largely upon the type of mineral being excavated (Strascraba & Abel, 2006). The way miners access the underground to reach the mine areas of gold is different from the way they access the underground to reach the oil wells. Largely, there are three different types of methods utilized in this case as discussed in the ensuing paragraph. The common method of accessing the underground is through the use of a shaft. A shaft, according to Wagner & Schumann (1991) and Kohlmeyer (2011), is a vertical excavation that has been sunk into the ground adjacent to a certain body of ore. In other words, it is an excavation that has been carried out in the ground parallel to the body that holds the mineral ore. From this shaft, horizontal excavations are then conducted to allow the miners to access the mineral ore and then the actual excavation is done. A decline, which forms another method of accessing the underground to allow the mining process to take place is a spiral tunnel or dug-up that goes round the ore deposits. At the surface, a box cut is made at the entrance to allow for the digging of this spiral form. Sometimes the tunnel is reinforced with steel in instances where the ground does not seem to be stable enough to be able to accommodate the weight of soil (Peterson, 1998). The steel prevents the ground from caving in. the other method is the use of adits. These are horizontal tunnels that are drilled into the ground most times into a hill to reach the body containing the ore and in instances when a shaft is not necessary. The process of excavation in underground mines This section will discuss the whole operation of mining underground, using case examples and diagrams to illustrate the process and establish the sustainability of the operation. The shaft underground mining process As seen earlier, shaft mining is among the three most utilized forms of mining in the underground. Shaft mining is also referred to as shaft sinking and the process involves the creation of vertical tunnels that run parallel to the ore body. However, as shall be found out, inclining shafts could also be used in this process. The following diagram depicts the whole process of shaft mining. Image source http://kids.britannica.com/comptons/art-53672/ From the diagram above that depicts the process of shaft mining, a number of observations into this process of excavation could be established. The initial step involves the creation of the vertical shaft that runs parallel to the ore deposits. From this tunnel, horizontal tunnels are then drilled into place moving on to the ore deposits. These tunnels are referred to as level and there could be as many levels as the depth of the vertical shaft could accommodate. The levels are also determined by the prospective presence of ore deposits and are dug with the aim of providing an access to the same. The miners are transported to these places using a cage which is hoisted on the vertical tunnel from a head frame that is pre – built on the mainland. Inside these tunnels, the miners drill their way into the ore deposits. Once they access the deposits, they then transport the ore back to the vertical shaft using rail carriages that are mostly manually driven. From there the cage takes them to the ground level for processing. At the bottom point of the shaft is a sump which represents the lowest point of the shaft. A lot of prospective drilling or mining in other words happens in this method of excavation. In a scenario where the ore deposit could be visible from the ground, like in the diagram above where the ore deposit is viewed as an outcrop, the miners place inclined shaft that run parallel to this ore and from this shaft, tunnels are dug in the same manner as through the vertical ones. This is referred to as a slope mine and the ore deposit is a vein. Once the ore deposits have been established, the miners make their way towards these deposits through a sense of prospecting and in different levels. The excavation is done and the ore transported to the surface where processing is carried out. This then brings us to another issue; how safe are these miners inside these mines? Safety of miners in the shaft excavation Once mining was discovered as a trade profession a long time ago, many people have perished in many mines across the globe. In the ancient times, security for the personnel who engage themselves in this business was highly compromised. One was never sure that he would survive another day inside the mines because of very many diverse factors. The constant looming fear of earth collapsing above these miners and burying them alive was always a fear factor inside these mines. There were massive casualties of these scenarios over the years. However, as the years progressed and the industry advanced in form of returns and technology, measures were put in place to protect the safety of these miners when they are at their work places under the earth. A vertical shaft, which forms the main tunnel in accessing the minerals could be described as being a little safer. However, since this tunnel is only used as a channel from which other tunnels are dug in a horizontal vector to enable access the of ore deposits which sit in parallel to the vertical shaft, the question of security of these tunnels or rather levels arise again. Earth is heavy, and the deeper the mines stretch into the ground, the heavier the soil weighs. For instance, from the diagram above, it can be seen that this particular mine has three levels of mining stretching from the vertical shaft. The third level could be termed as being more dangerous and at a higher risk than the first level. This is because on level three, there is a lot of weight above it coming from the increased depth and volume of earth. This then implies that extra caution and security measures should be applied when conducting an excavation on level three. One of the best ways to protect the safety of the miners is through the reinforcement of these tunnels using reinforced steel. The tunnels walls are coated with reinforced steel inform of an arc at the roof. This takes care of the earth above that would have otherwise crumbled under the slightest form of weakness or provocation. Some of the mines keep health stations inside these mines. These stations act as the point of referral when in a case of emergency. These stations are equipped with qualified personnel who are designed and knowledgeable in the handling of casualties and cases inside the mines. They keep a fresh supply of air and other chemicals that are designed to neutralize any form of poisonous gases that could emanate from the ore deposits or due to the congestion in the mines. Tools used in mining It cannot be emphasized more that different methods of minerals require different forms of mining. The same applies to the tools used. The difference is dictated by a number of factors such as hardness of the ore, the chemical composition of the ore and even the size. Mining of gold for instance requires tools designed as the following paragraphs detail. In early times, the miners used tools that were primitive. The most common basic tools used in mining are picks, shovels, axes, wheelbarrows and drill guns. Today, these tools have become very advanced and in line with the advancement in technology. Tools used in mining relate to the stage of mining that is carried out. For instance, in the benefaction stage where the minerals are separated, tools such as floatation plants, gravity plants and magnetic separation plants are present. In the mining stage there are tools such as floatation machines, shaking table, Sawtooth wave jigger, spiral separator and shaking table. There are also crushing machines and grinding machines (Henan Leili mining machinery website, 2013). There are different materials used for cutting heads (Chaamwe et al, 2010). For cutting gold, the tool used must have a carbide head. Shaft mining as an environmental hazard As much as it is benefit to the economy is momentous, shaft mining presents a problem to the environment. Shaft mining is one of the most dangerous form of environmental pollution. This is because it involves drilling of holes into the ground that could be potentially harmful or even outright dangerous in the future. Some of these holes are as deep as three kilometers long and they present avenues for fatal accidents to occur. Once the lifespan of the mines is over and the ore deposits are exhausted, the mines are dumped in favor of new mining grounds. These dumped mines remain closed for a long time following the notion that nothing could be made from the areas and buildings could not get erected over these shafts for fear of collapse. Case study: South Deep Twinshaft complex South Deep Twinshaft complex is a mine that is located in Westonaria, Gauteng in South Africa (Czernowalow, 2005). South Deep Twinshaft complex is deemed to be among the world’s deepest mine with a shaft that drops into the earth for nearly three kilometers. The mine project cost the prospectors an averaged four billion Rands to build over a span of ten-year period. The estimated returns of the mine once the deposits have been excavated are also as staggering, being estimated to be in reserves of over 56 Million gold ounces. The life span of the project is 60 years. The mine, expected to be cash positive and to have broken even in five years time utilized over 7700 tonnes of steel during its creation, making it one of the most expensive and largest mine in the world. Conclusion The discussion made in this report has outlined quite clearly upon the process used in underground mining and with special focus on the shaft mining. The report has also shown how this industry benefits the economy. On the contra side, it has been established that these mines cause environmental degradation and sometimes-outright pollution. A case study has been used to show the financial aspect of the mining industry and the prospects of the same in the future. Recommendations Following the above discourse, this report offers recommendations as highlighted in the following paragraphs. The government should come up with ideas on how these dumped and unused mining sites could be put to constructive use to avoid this wastage and environmental waste. Mining companies should invest more in ensuring that the safety of their workers is guaranteed and that the tunnels in these mines are well aerated and free from diseases especially communicable ones. References Chaamwe et al (2010). An Assesment of Underground Mine Enviromental Monitoring Methods at Zambia’s Copper Mines, Research Journal of Applied Science, Vol. 5 (5), pp.345-351. DOI: 10.3923/rjasci.2010.345.351 Czernowalow, M. (2005). World's deepest single-drop shaft opens, Retrieved September 15, 2013 from http://www.miningweekly.com/article/worlds-deepest-singledrop-shaft-opens-2005-02- 07. Henan Leili mining machinery website (2013). Mining machinery, retrieved September 15, 2013 from http://www.leilimining.com/products/Application.html Kohlmeyer (2011). Modelling and control of an articulated underground mining vehicle, master’s thesis, retrieved September 15, 2013 from http://upetd.up.ac.za/thesis/available/etd-07122012-181940/unrestricted/dissertation.pdf Mining image, retrieved from http://kids.britannica.com/comptons/art-53672/ Peterson, R.D (1998). Surface assisted continuous underground mining, conference paper, Feb, 1998, retrieved September 15, 2013 from http://ro.uow.edu.au/cgi/viewcontent.cgi?article=1291&context=coal Strascraba & Abel, 2006). The differences in underground mines dewatering with the application of caving or backfilling mining methods, Mine water and the environment journal, Vol. 13, No, 2. Pp. 1-20. Wagner, H & Schumann, E (1991). Surface effects of total coal-seam extraction by underground mining methods, Journal of the South African institute of mining and metallurgy, Vol. 91, No. 7. pp. 221-239. Read More

Once they access the deposits, they then transport the ore back to the vertical shaft using rail carriages that are mostly manually driven. From there the cage takes them to the ground level for processing. At the bottom point of the shaft is a sump which represents the lowest point of the shaft. A lot of prospective drilling or mining in other words happens in this method of excavation. In a scenario where the ore deposit could be visible from the ground, like in the diagram above where the ore deposit is viewed as an outcrop, the miners place inclined shaft that run parallel to this ore and from this shaft, tunnels are dug in the same manner as through the vertical ones.

This is referred to as a slope mine and the ore deposit is a vein. Once the ore deposits have been established, the miners make their way towards these deposits through a sense of prospecting and in different levels. The excavation is done and the ore transported to the surface where processing is carried out. This then brings us to another issue; how safe are these miners inside these mines? Safety of miners in the shaft excavation Once mining was discovered as a trade profession a long time ago, many people have perished in many mines across the globe.

In the ancient times, security for the personnel who engage themselves in this business was highly compromised. One was never sure that he would survive another day inside the mines because of very many diverse factors. The constant looming fear of earth collapsing above these miners and burying them alive was always a fear factor inside these mines. There were massive casualties of these scenarios over the years. However, as the years progressed and the industry advanced in form of returns and technology, measures were put in place to protect the safety of these miners when they are at their work places under the earth.

A vertical shaft, which forms the main tunnel in accessing the minerals could be described as being a little safer. However, since this tunnel is only used as a channel from which other tunnels are dug in a horizontal vector to enable access the of ore deposits which sit in parallel to the vertical shaft, the question of security of these tunnels or rather levels arise again. Earth is heavy, and the deeper the mines stretch into the ground, the heavier the soil weighs. For instance, from the diagram above, it can be seen that this particular mine has three levels of mining stretching from the vertical shaft.

The third level could be termed as being more dangerous and at a higher risk than the first level. This is because on level three, there is a lot of weight above it coming from the increased depth and volume of earth. This then implies that extra caution and security measures should be applied when conducting an excavation on level three. One of the best ways to protect the safety of the miners is through the reinforcement of these tunnels using reinforced steel. The tunnels walls are coated with reinforced steel inform of an arc at the roof.

This takes care of the earth above that would have otherwise crumbled under the slightest form of weakness or provocation. Some of the mines keep health stations inside these mines. These stations act as the point of referral when in a case of emergency. These stations are equipped with qualified personnel who are designed and knowledgeable in the handling of casualties and cases inside the mines. They keep a fresh supply of air and other chemicals that are designed to neutralize any form of poisonous gases that could emanate from the ore deposits or due to the congestion in the mines.

Tools used in mining It cannot be emphasized more that different methods of minerals require different forms of mining. The same applies to the tools used. The difference is dictated by a number of factors such as hardness of the ore, the chemical composition of the ore and even the size. Mining of gold for instance requires tools designed as the following paragraphs detail.

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