Bauxite Mining In Guyana.docx

BAUXITE MINING IN GUYANA What is Bauxite? Bauxite is a mineral used to make Aluminium. Aluminium is a lightweight metal used in the manufacture of many products such as cooking foil, aircrafts, buses and other vehicles as well parts of many appliances. Bauxite is extracted from within the earth and refined to make Alumina, which is pure aluminium oxide. The alumina (which is a white powder) is further processed to make aluminium. Importance of the bauxite industry in Guyana - manufacture of aluminium, which is required in large amounts, and other products - provides employment – over 8,000 workers are employed in the industry - earns foreign exchange through export - Guyana produces the world’s best refactory grade bauxite i.e. more alumina can be obtained from a tonne of Guyana’s bauxite than bauxite from other countries. Alumina content can be as high as 70% compared to Jamaica’s 47%. - Guyana’s reserves are expected to be around 500 million tonnes, hence the industry makes use of one of Guyana’s major natural resources.

USES:

- to produce Aluminium (in Guyana) – to make firebricks to line kilns and furnaces - to make special cement to withstand high temperatures - to make high-strength porcelain for electrical insulators - for anti-skid surfacing for roads, factory floors and airport runways - to produce aluminium sulphate and other chemicals.

Location within Guyana Deposits/reserves – bauxite exists in a fan-shaped belt extending some 320 km from Bartica on the Berbice River eastwards towards the Canje district. It’s width fluctuates between 25-35km. Mining Areas

- Linden and Ituni along the Demerara River Kwakwani and Everton along the Berbice River

Alumina plants

- alumina plants are located at Linden (along Demerara) and Everton (near the Berbice River)

MINING/EXTRACTION Mining of bauxite is done in stages: 1- Surveying is done to find large deposits 2- Removal of overlying layers using bulldozers 3- Primary Stripping- removal of the topsoil or overburden – bauxite is buried beneath deposits of clay and sand which are in places over 60 m thick. Powerful hoses, bulldozers and draglines are used to strip off the thick overburden. 4- Secondary Stripping- this is the actual mining or removal of the ore. Drilling and blasting using dynamite are used to loosen and break up the ore. The bauxite is loaded using hydraulic excavators into trucks and then taken to stockpiles.

Transport Trucks take the bauxite to the stockpiles where it is crushed. The crushed ore is taken by large trucks or railway wagons to the refineries. The bauxite is also loaded onto barges and transported along the Berbice and Demerara Rivers.

PROCESSING OF BAUXITE INTO ALUMINA (ALUMINIUM OXIDE) 1- Milling – or crushing of the bauxite 2- Desilication – removal of silica 3- Digestion – aluminium bearing minerals are dissolved using a hot caustic soda 4- Clarification/Settling – a filtration process removing solids 5- Precipitation – recovery of alumina minerals by formation of small crystals 6- Classification – crystals are classified according to size – large crystals move on to the next stage while small crystals are sent back to the precipitation stage as fine seeds to be agglomerated. 7- Calcination – the crystal product is roasted at temperatures of up to 1100oC. Alumina, a white powder is the result of this step (the final product) PROCESSING OF ALUMINA INTO ALUMINIUM Smelting of alumina into metallic aluminium takes place in a steel vat called a reduction pot. The bottom of the pot is lined with carbon which acts as one electrode (conductor). The opposite electrodes consist of a set of carbon rods suspended above the pot. Within the smelting pot the alumina is dissolved to form an electrolyte solution that will conduct electricity from the carbon rods to the carbon lined beds of the pot. A large direct current is passed through the solution breaking the bonds between the aluminium and oxygen atoms. The oxygen that is released is attracted to the carbon rods, where it forms carbon dioxide. The freed aluminium atoms settle

to the bottom as molten metal. The molten metal is then removed and cooled thereby solidifying.

ENERGY REQUIREMENTS Aluminium smelters require a very large input of electrical energy. Energy production must be cheap and abundant in order to be economically viable. Trinidad , therefore, is a possibility due to its oil and gas production. Attempts to construct and operate an aluminium smelter here has been met with strong protest due to environmental concerns. Jamaica remains a candidate as it operates five hydroelectric power plants. While initial set up is expensive, once in operation, can provide a cheap, abundant and reliable supply of electricity. While Guyana has the potential for Hydroelectric power (HEP), they have not been able to implement HEP plants, one of the main deterrents being the high cost of installation. Most other Caribbean countries do not possess large rivers or raw materials (oil and gas) required for abundant electricity generation.

MARKETING Bauxite and alumina are exported for processing into aluminium to the U.S.A. (it is shipped to Chaguaramas, Trinidad as a transshipment point and then to the U.S.A. via ALCOA – the Aluminium Company of America) and Canada (via ALCAN – the Aluminium Company of Canada). Other importers of Guyana Bauxite include China, India Ukraine and Ireland.

PROBLEMS OF THE INDUSTRY 1- Mining costs can be very high as overburden can be very thick in parts 2- Shipping costs are high 3- Processing plants are not operating at full capacity – this increases cost 4- Mining and processing bauxite employs only a small percentage of the workforce 5- Many top management positions are held by foreigners 6- Environmental/Health Issues – - Deforestation and removal of topsoil (overburden) – results in destruction of animal habitat, death or migration of animals. Loose and unprotected soil becomes blown away by wind or or washed away by rainfall, resulting in sedimentation of rivers (further affecting ecosystems and causing flooding). - Airborne dust, when inhaled, can cause respiratory illnesses. Long term exposure to bauxite/alumina (especially when

inhaled) can result in skin and eye irritation and pain. Studies have shown materials found in bauxite (aluminium hydroxide, iron oxide, titanium oxide and silica) could lead to neurological problems such as chronic brain syndrome, anxiety for no reason, Alzheimer’s and Parkinson’s disease in adults. They can affect the functioning of the liver system. High concentrations may cause shortness of breath, chest pains, fatigue, fainting or even death. Long exposure can cause inflammation of the lungs which can cause chronic bronchitis. - By-products of the smelting process - carbon dioxide, sodium flouride and sulphur dioxide – are greenhouse gases. Other particulates from combustion compromise air quality.