Extensive environmental baseline data are collected prior to mining in order to evaluate potential impacts from mining. Mining, reclamation, and mitigation plans are reviewed and approved by the appropriate federal, state, and country regulatory agencies prior to initial mining activities.
2. Vegetation Removal
Based upon the approved plan, vegetation is removed from the area to be mined. Usually, a combination of logging, cutting, and stacking trees for firewood and transplanting smaller trees to reclaimed areas are used to conserve woody resources.
3. Topsoil Handling
Dozers, loaders, and trucks are used to collect salvageable topsoil for storage until it can be used for reclamation.
4. Mining
The mining process includes controlled blasting, hauling, crushing, leaching, processing, and beneficiation for the recovery of gold.
5. Backfilling, Contouring, and Re-grading
Overburden rock is places either in engineered storage areas or used to backfill mined areas according to the approved reclamation plan and shaped to establish a stable post-mining slope.
6. Topsoil Replacement
After re-grading, salvaged topsoil is replaced, and fertilizers and other amendments are incorporated in order to prepare a suitable seedbed.
7. Revegetation
Newly resloped and topsoiled areas are seeded annually in the fall with a mix of grasses, forbs, and shrubs known to establish successfully in the region. Following establishment of a permanent vegetative cover, seedings from the trees in the permitted area are transplanted by hand, on at a time.
8. Monitoring for Sustainability
To ensure that a stable and productive post-mining land use has been re-established, monitors and evaluates reclaimed areas is needed for several years following the reclamation process.
The Mining Process
Where to Dig
Nowadays, the process of gold mining is very complex. It starts with a well structured plan but not directly excavate the mine with tools and equipment. First, a mining company will make sure the funds is sufficiently enough for the purpose of setting up the necessary equipment and to execute the recovery of the gold should it be found. The next step will be hiring geologists and specialist to analyze the rock contents in a specific geographic area. The main interest that the specialists look for at the mining area will be things like igneous rocks, quartz and ore which indicates gold may be in that area.
Starting the Extraction
Once the determination has been done to confirm that there are high possibility to find a huge amount of gold in that particular area, the gold mining company will begin their operation. Generally, in the mining area, large machines is required to pulvarize rock, ply away soil and basically strip down the earth until they reach the “pockets” where gold is located. In mining, “pocket” will be defined as a pit which filled with ore or different kind of precious metal. In some cases, the mining process requires drilling through solid bedrock, followed up by creating a mine shaft with specialized digging equipment. The mine shaft is built to intersect the gold pockets, and workers are then dispatched to extract the gold.
Recovery
Sometimes, gold can only be found in a tiny portion throughout the ore in the soil. In order to remove the gold from the dirt, extraction methods can be used. After all, once the gold ore is completely removed from the ground, the rocks will be sorted and crushed into fine powder, then this is mixed with a solution and turned into sludge. The sludge will be then stored in tanks and then sent through a ” clarifier” and finally through a filter where the gold is separated from the liquid and recovered.
The following are the mining process in details:
1. Location Drilling
The active mining process begins with the drilling of blast holes, approximately 40 feet deep and 16 to 22 feet apart. The drill holes are located by Global Positioning System (GPS) mapping technology. The drill cuttings are sampled to confirm gold content.
2. Blasting
Controlled blasts of the drill holes break the rock and minimize movement. Controlled blasts help limit ground vibrations that are carefully monitored ensure the vibrations are within strict permit limits.
3. Mining
The broken rock, called muck, is surveyed and marked with flags to indicate gold-bearing ore and non-gold bearing rock referred to as “overburden”.
4. Hauling
Large dump trucks are then used to move the ore to the primary crusher for processing. The overburden is backfilled to previously mined areas or is moved to engineered storage areas.
5. Crushing
One is processed at the two-stage crushing and screening facility and hauled to Valley Leach Facility (VLF).
6. Leaching
The VLF is a double-lined, and in some areas triple-lined, zero-discharge area where the gold is recovered. A dilute solution of sodium cyanide is applied using agricultural-type drip irrigation tubes, which are buried under the crushed rock surface to dissolve the gold. The gold-bearing solution is captured at the bottom of the lined area. The solution containing the gold is called ” pregnant solution”.
7. Processing
The gold is recovered from the pregnant solution with a carbon adsorption process. The gold laden carbon is processed to create a gold-rich mud. After the gold is recovered, the solution with no gold, called “barren solution”, is reconstituted and then re-circulated to the VLF to repeat the gold recovery process.
8. Pouring:
The gold-rich mud is sent to the refinery furnace and heated to separate the gold and silver from any non-metal substances. The resulting 98% gold-silver mixture is called dore (daw-rey). The dore is shipped to specialized refinery to be processed into 99.999% pure gold or 24 karat.
2.1 Definition
According to Wikipedia, gold mining consists of the processes and techniques employed in the removal of gold from the ground. Golf mining can be expounded in another way where several terms is added to elaborate the definition of gold mining, the specific terms includes exploration of gold mining, drilling, geological assessment, financing, development, extraction, initial refinement, and delivery of gold bars to a bullion refiner. Besides, gold mining can also refer to as a mine where gold ore is found. Sometimes, human being relates the things that they desired and the source of wealth with gold mine, because gold is a kind of metal that symbolize wealth and a store of value.
2.2.2 Country of gold mining
Based on the list of top gold producing coutries as provided by British Geological Survey on 2006, the top three countries that have the highest production of gold are Russia, China, and Australia. The total production of gold by countries from all over the world that produced on the year of 2006 was 2,310,000 kilograms.
Below table shown the ranking of countries with top production of gold in 2006:
Russia
Russia has overtook China, Australia, and United States to become the world’s top country that produce the highest amount of gold during the year of 2006 according to the Bristish Geological Survey that accessed in July 2008. Being the top producer of gold, Western gold mining companies has an very great impact on it while these company are very active in Russia and managed to developed a successful track record as well as shown both rising production and profitability. Besides, a thorough understanding of the licensing process, legal environment, coupled with the developments of relationships with local partners, has also played an important role in the success of these companies. However, there is also a risk which will probably influence the mining performance in Russia while the foreign companies have had mining licences terminated or suspended.
The map shows the mining project site in Eastern Russia.
China
In 2006, China overtook Australia, United States and Peru to become the world’s second largest gold producer. Today, China almost leads the world in gold mining output which also bring to a great raise of gold production over the year. In year 2006, China has produced 247,200 kilograms of gold based on the Bristish Geological Survey. According to sources of information provided by Gold InfoMine, the production of gold has usually been focussed in the eastern provinces of Shandong, Henan, Fujian and Liaoning. Recently, western provinces such as Guizhou and Yunnan have seen a sharp increase in their gold output.
China is utilizing the advancement in metallogenic theory and exploration methods for Carlin-type (Nevada) gold deposits by American geologists. There are over hundred Carlin-type gold deposit occurrences have been recognized in southwest and central China.
From the map above, the orange shaded area shows the sedimentary rock-hosted gold district in China which located at Jidong Area, Qin Ling Fold Belt, and Dian-Qian-Gui Area relatively.
Australia
Australia is now the world third largest gold producer. The gold production in Australia do not only concentrate in a particular state or area. However, gold can be found and produced all over in Australia. Among other states in Australia, Western Australia known to be the largest gold producing state and manage to produce two third of the nation’s gold total output. Besides Western Australia, New South Wales and Queensland are also a considerably large producers in Australia.
The yellow shaded area in the map shows the mining sites of Australia.
United States
Gold mining in United States is unlike Australia that the gold is produced all over in that country. It merely focus on the states of Nevada, Alaska, Utah, and Colorado. There are also gold operations and exploration projects in Arizona, California, Idaho, Montana, New Mexico, South Dakota, Utah, and Washington. Nevada is the state that leads United States in gold production with highest amount output of gold compare to other state. Mines in Nevada amounted to almost 82% of domestic production in year 2006. Nevada applies the technique of open pit mining and the gold is recovered by means of cyanide heap leaching. The largest gold operation in Unites States is the Carlin mine in northeast Nevada, which is producing gold from a large low-grade deposit.
The map shows the mining area in United States.
Peru
Peru ranked as the top five largest gold producer throughout the world. In Peru, Inca and the Mariategui Regions produced most of the placer mines. Placer mines can be also found through rivers and streams all over in the jungle. The Inambari River in Peru and its tributaries signify a well known placer zone situated in southeastern Andes.
One of the largest and gainful mine in Peru is The Yanacocha mine in Andes the northern Peru. The Yanacocha mine also known as one of the world biggest mine. Gold deposits in Yanacocha are high sulfidation epithermal gold deposits, with varying amounts of silver. The Yanacocha gold district within a belt of Tertiary volcanics is a 10 km x 4 km zone of altered rocks that extends the whole length of Peru.
The map shows the location of Yanacocha Gold Mine in Peru.
South Africa
According to the British Geologicall Survey as accessed in July 2008, South Africa known as the top 6 gold producer in the world. Almost the entire gold mine in South Africa are underground operations. The output of the gold in South Africa highly rely on the production cost, power interruptions, personnel problems, depth of mining and lastly the most significant criterion is the ore grades.
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South Africa has numerous gold ore reserves. Archaean Witwatersrand Basin is the main gold producing mines in South Africa. This basin has been mined for not merely 100 years and has produced more than 41,000 t of gold. Dissimilar with most of the world’s major gold deposits, the Witwatersrand is an ancient placer deposit, with gold being hosted by conglomerates and grits. The Witwatersrand sedimentary basin stretches through an arc of approximately 400 km across the Free State, North West and Gauteng Provinces.
The area shaded in blue shows the goldfield in South Africa.
2.2.3 How to measure gold’s value?
Gold appears in many forms and this comprising of gold bars and gold coins which we using it everyday to trade something that we wanted. Most gold in the market is not in pure form in virtue of the attributes of gold. Gold is rather soft that we can easily damage it. Solution taken to overcome the frailness of gold is that we alloyed gold with another metal to make it solider and durable. Is is a complicated task in finding the value of the gold in a piece of jewelry. First, to measure gold’s value, we may have to convert the weight of gold into Troy ounces rather than grams or regular ounces. Since Troy ounces is the measure used as the price of gold is quoted on world markets.
The guides on the measurement of gold’s value:
Step 1:
Gauge the item of gold using a presicion scale. We must convert the unit into Troy ounces if the scale is calibrated in grams or regular ounces. To convert the unit of measurement into Troy ounces, divide the weight in grams by 31.10 to find the weight in Troy answers.
Formula from grams convert to Troy ounces:
Formula from regular ounces convert to Troy ounces:
For example:
If the project weighs 88.85grams. divide 88.85grams by 31.10 for a weight of 2.86 Troy ounces.
Step 2:
Determine the proportion of actual gold. To verify the karat weight of the gold item, we may refer to the jeweler’s mark located on the Gold jewelry. In general, the purity of gold is rated in karats. Pure gold rated as 24K(karats). However, most gold jewelry only ranges from 14K to 22K. This indicates that the gold jewelry contains that portion size out of 24K of real gold. For instance, 15K gold jewelry contains 15/24 (62.5 percent) gold. Gold bars have the ratio of gold stamped on them. For coins, we may look up the type of coin in a catalogue as provided by Professional Coin Grading Service.
Formula in calculating the percentage of gold contains in a 15K gold jewelry:
62.5% here indicates the portion of real gold contains in that 15K gold jewelry.
Step 3:
Find the amount of gold in Troy ounces. Multiply the weight in Troy ounces as we obtained from Step 1 by the percentage of gold in the item from Step 2.
For example:
Find the amount of Troy ounces which contains 2.86 Troy ounces and 62.5% (15K) actual gold.
This means that the item consists of 1.7875Troy ounces of gold.
Step 4:
Calculate the gold value of the item. Gold known as a commodity and the value of gold differs from day to day as it is traded on world markets. The current price or value of gold per Troy ounce is quoted daily on many websites and newpapers. Multiply the current price of gold by the number Troy ounces to find the gold value.
For example:
Suppose the current price is RM900 per Troy ounce. Using the previous example, we multiply 1.7875 by RM900. The gold value works out to RM1,608.75.
The answer shows that the gold value works out to RM1,608.75.
2.2.7 Impact of gold mine on the environment
2.2.4 Benefits of gold mining
It gives us access to necessary minerals and
material that we use constantly.
Mining gives jobs and makes money, as well as giving us all the materials we need, so it
is very good in that sense.
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