Mineral Resources
Minerals are gift of nature which is non-renewable resource .eg. Coal, iron, and other metals and non-metals are various minerals, obtained by mining and metallurgical processes.
The large-scale exploitation of minerals began in the Industrial Revolution around 1760 in England and has grown rapidly over the ages. Today's economy is largely based on fossil fuels (coal, petrol and diesel), minerals and oil.
Categories of Mineral Resources:-
There are four categories the mineral resources:
A] Metals e.g. copper, aluminum, iron etc.
B] Industrial Materials e.g. lime, potash, salt, marble gemstones-diamond, rubies etc.
C] Construction Materials e.g. sand, stone, gravels etc.
D] Energy Minerals e.g. coal, oil, gas, heavy radioactive metals like Uranium, Thorium, Radium etc.
Basics of Mining Activities
•Lot of building materials are obtained from mines. Demand of stones, marble, granite, limestone, etc is ever increasing.
•To support 8-9% of GDP growth, mining sector has to do well.
•Value of the minerals increases because of the large demand, and supply is inadequate.
•This has resulted into more efforts to drill and search other territories.
•The environment is being misued and "depletion" of resources is one of the effects.
•Mining is done on a location where stock of mereral/ore deposit is identified by geologists. When minerals present in earths crust at a particular location are in sufficient concentration, then only the mining proves to be economically viable.
1.Geophysical survey: Involves measurement/evaluation of air where magnetic or density variations (anomalies) are indicated. Such areas are identified as "Prospective" for mineral deposits.
2.Mapping: Surface is studied to understand configuration.
3.Sampling:Stream sediments from prospective area are collected. Trenches are dug across the "Prospective" area. The samples are analysed to get mineral composition.
4.Drilling: On the basis of above analysis, drilling is taken up at prospective site, using diamond-encrsuted circular drills.
5.Modelling:It is done I'm recent years by computers, to know grade and configuration of the mineral.
6.Feasibility: At this stage, a decision is taken considering profitability of mining operation for country/area. The major parameter at this stage to be considered is for raising funds for entire project. It is also known as "banking feasibility study", because it is used for securing funds.
Steps in mining :
1.Dredging:
If mining site is near water area, or in shallow water or under sea, this technique is followed. eg. Gem diamonds in shallow water.
2.Surface mining:
This technique is chosen in following ways:
a) If rock is soft: Open cast mining is done e.g. for coal or limestone. It is drilled on surface, upto 200m depth.
b) If rock is hard:Open pit mining is done e.g. copper diamonds. It is done by drilling/blasting and then broken ore- rock pieces are taken to processing plant.
3.Underground mining.
4.Insitu mining: This is done in two ways.
a) Solution: Water is injected on drill holes, to pull soluble mineral e.g. salt. Then it is again pumped beck on surface, followed by further processing.
b) Thermal:Useful for coal mining [still on research stage]
"MINE SAFETY:"
It is well known fact that mining activity is harmful for environment. Certain safety measures can minimize/control harmful effects.
i)Strong global and local legislations are required to reverse the trend. Governments need to show more strong political will to preserve our resources.
ii) Use of synthetic building materials can reduce the load on natural stones.
iii) Use of new technologies at thermal power plants, ignition engines, metallurgy, industries etc so that more outputs obtained from low inputs.
iv) Tree plantation between area of mining and habitat may curb the pollution.
1]Mines: The underground mines must have ventilation in such a way for efficient removal of CO2, CO, NOx, SO2, etc. which are produced due to burning of fuel in mining equipments/Blasting operations/from ores.
2]Disaster management system to handle mining accidents must be in place. The miners must be trained for technique/handling of such situation.
Effects of Mining of Environment
I) Mining has resulted in more efforts to drill and search for other territories which are enriched with minerals.
II) Mining pollutes the environment, on a large scale.
III) Accidents related with landslides are common in coal mining areas.
IV) Onshore mining processes badly affects marine life.
V) Mining activity produces large amount of waste.
VI) Mining causes soil erosion- which is 10 times more than that caused by all rivers taken together.
VII) Mining and mineral industry causes air pollution. Hectares of land becomes uninhabitable,
VIII) It causes birth deformities and related illnesses which affect humans years after years.
#Various techniques for setting a safe working environment.
LIDAR SCANNER
This technique is now becoming common in the mining industry because it provides in-depth geotechnical data analysis with regards to slope instability. The laser imaging system or 3-D scanner comes with the advantages of speed, accuracy, precision and it is user-friendly. The system has the ability to gather all the geotechnical data of the area concerned at once,unlike the total station which takes or make one measurement at a time. With the system being able to scan a distance of up to 2.5km with the accuracy level of +/- 25mm, it can acquire approximately
10000 data points per second. From the slope data collected by the system, movement of the slope can be analysed.
GLOBAL POSITIONING SYSTEM (GPS)
The Global Positioning System (GPS) was first developed as a system for navigation but has now recently been used as a method for surveying. GPS has been introduced in open pit mining operations for monitoring walls and/or slope deformation/instability. GPS has the ability to monitor 3-D displacements over a broader area than conventional monitoring systems and it has a high level of accuracy. As a monitoring system in surface mines the GPS uses a method called relative positioning unlike point positioning used for navigation. For monitoring rock displacements, relative positioning provides the control room server with 3-D relative coordinates between two points. The displacement of the rock is found by calculating the changes in the coordinates.The GPS uses sensors, antenna, control box and a computer. Data is received by antennas from the GPS satellite located in space and is then computed or analysed in the control room to give real time
results. Researchers in the field of rock engineering have proposed a new model that yields more accurate results than conventional GPS method (Standard Deviation method). This model is called the trend model. Again for better results and interpretation of the results of the GPS, a Back Analysis method of the measured displacements was introduced. With back analysis the strength parameters of the rock can be determined based on the mathematical calculations of the measured displacements from the GPS. After getting the strength parameters then the factor of safety of the slopes can be calculated.
SLOPE STABILITY RADAR (SSR).
The slope stability radar is an innovative technology which has recently been adopted by the mining industry. This innovative technology is based on radar technology to remotely scan pit slopes to monitor any deformation of the face. SSR is very advantageous in a sense
that it gives early warning signals of potential highwall or slope failure. The other advantage of this technique is that even in harsh atmospheric conditions the system can still operate to its maximum potential. The system is calibrated with four coloured alarms; Red alarm indicates an emergency situation and persons are removed to safety; orange alarm indicates displacement of the wall and rock engineering department should be notified; yellow alarm indicates system failure and the rock engineering department is notified to assess the SSR and the green alarm indicate a minor failure of
the SSR and a reboot of the system occurred. Another advantage of the SSR is that it does not need to be installed permanently in one place; it can be moved around the mine to take measurements for comparing movements along the slopes and identifying which areas are hazardous.
TIME DOMAIN REFLECTOMETER
The Time Domain Reflectometer is an electrical method used in surface mines for locating discontinuities in the conducting material or cables. TDR is used to monitor rock or soil movement and highwall slope in surface mines. The technology uses coaxial cables which are grouted in boreholes drilled in the slope. These coaxial cables are inserted in the borehole and when there is movement of the slope it will cause a fault in the cable which is then
measured by the cable tester; the movement causes what is known as “reflections” along the cable
and these are logged into a software and analysed by a geotechnical engineer. The benefits of this technology are increased safety, high accuracy, inexpensive and the ability to monitor deformation along the entire length of the cable.
Most common bothering:-
DUST
Surface mines are also well known for their level of dust produced at their operations. Dust is a major concern in surface mines as it affects not only the mine employees but also the community in which the mine is located. Sources of dust in surface mines are drilling and blasting activities, in-pit crush-
ing, handling/loading and transportation.
Over the years dust has been a major
cause of occupational diseases associated with prolonged exposure to dust. These occupational diseases include:
•Silicosis
•Tuberculosis (TB)
•Bronchitis
•Emphysema
•Anthracosis and
•Pneumoconiosis
With the above said, it is extremely important that strict legislation is tabled so as to ensure that
mines combat or minimise the level of dust particles which employees and the community at large are exposed to.
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