16510015049500 Department of Mining Engineering and Mine Surveying
Module: Mining Engineering Practice 1B
Learning Unit: 3
Student number: 201592553
Initials: K Surname: MOLOTO
Assessor: (Mr, H, Strauss)
Portfolio instructions (as given by assessor): You are required to compile a portfolio that summarises what you have learnt during the activities associated with learning units 3. You are also required to reflect on each section of work and consider how this will be applicable to you in your future career as a mining engineering technologist.
Learning outcomes and assessment criteria (To be completed by student).
No Outcome Assessment criteria
1 Awareness of the basic activities in the mining production cycle.
Be conversant with production mining terminology as used in industry. Present a coherent mining production cycle, and describe the essence of each part. Name the roles, tasks, and responsibilities of production mining personnel. Name the production equipment and material used in mines.
2 Basic knowledge of underground mining methods.
Be conversant with underground mining terminology as used in industry. Describe how a mineral deposit is exploited with under-ground mining methods.
Specific Outcome 1. Role of Engineers and Technologists.
What is a mining engineer?
A mining engineer is a person who applies his/her ranged science and technology skills set to extracting minerals from the earth, making it a multidisciplinary role. They come up with ideas and systems to make mining safer, cleaner and more efficient.
What should a mining engineer be doing?
Before a mining process can take place, mining engineers carry out a feasibility study and environmental assessments to determine the commercial advantages and any issues relating to sustainability.
supervise the construction process and manage the engineering parts of the production once a mine is open for business.
ensures that a mine is developed in a safer and effective way and supervise any other surface and underground operations.
supervises samples taken and presents them to managers.
make systems more effective and safe for miners.
assists in mineral deposits discovery, supervise shaft construction and examine mines for safety issues.
manage and supervise mining production process.
They are also involved in the final closure and rehabilitation process.
What is a mining engineering technologist?
A mining engineering technologist is a person responsible for the safety, effectiveness and cleanliness of mines. They generally work alongside mining engineers.
What should a mining engineering technologist be doing?
A mining engineering technologist assist mining engineers with:
travelling to mines, doing investigations and researches.
designing new and safer equipment.
Designing of tunnels and shafts.
making sure that mines and miners are safe.
What is a mining engineering technician?
A mining engineering technician is a person responsible for providing technical assistance to mining engineers and engineering technologists. They are also responsible for keeping a mine clean and safe.
What should a mining engineering technician be doing?
They work in:
exploration and development, where they work with geologists and geophysicists.
Preparation/beneficiation, where they separate the valuable ore from the rock and other worthless materials.
Laboratories, where they test samples of rock and ore.
engineering offices of mining operations, where they help engineers with designing and installation of ventilation systems which provide fresh air into the mine shafts.
collect information by carrying out chemical and physical tests and observing mining operations.
assist surveyors, chemists and metallurgists.
collect and identify samples of the rock mined.
train new miners and make sure that safety rules are strictly followed.
Engineering disciplines involved in mining
Mining: comes with the best plan to extract an ore from the ground and helps with designing the whole mining operation.
Geological: examines ore bodies and give directions on where the ore is to be found.
Mechanical: designs new machinery.
Electrical/ electronic: preserve and check for any electrical fault in the panels to make sure there is a smooth supply of power.
Metallurgical: work in the processing stage, where they separate the valuable fraction from an uneconomic fraction.
Chemical: involved in operation and improvement of beneficiation and processing plants.
Environmental: makes sure that wastes are safely disposed of and comes up with plans on how to deal with emergencies.
Industrial/ process: deals with evaluation and improvements of operations.
Specific Outcome 2. ECSA ELOs applicable to the BEng tech programme.
Exit Level Outcome 1: Problem Solving.
Apply engineering principles to systemically diagnose and solve broadly-defined engineering problems.
Exit Level Outcome 2: Application of scientific and engineering knowledge.
Apply knowledge of mathematic, natural science and engineering sciences to defined and applied engineering procedures, process, systems and methodologies to solve broadly-defined engineering problems.
Exit Level Outcome 3: Engineering design.
Perform procedural and non-procedural design of broadly defined components, systems, works, products or processes to meet desired needs normally within applicable standards, codes of practise and legislation.
Exit Level Outcome 4: Investigation
Conduct investigations of broadly-defined problems through searching, locating and selecting relevant data from the codes, data bases and literature, designing and conducting experiments, analysing and interpreting results to prove valid conclusions.
Exit Level Outcome 5: Engineering methods, skills, tools, including information technology.
Use appropriate techniques, resources, and modern engineering tools, including information technology, prediction and modelling, for the solution of broadly-defined engineering problems, with an understanding of limitations, restrictions, premises, assumptions and constraints.
Exit Level Outcome 6: Professional and technical communication.
Communicate effectively, both orally and in writing, with engineering audience and affected parties.
Exit Level Outcome 7: Impact of engineering activity.
Demonstrate knowledge and understanding of the impact of engineering activity on the society, economy, industrial and physical environment, and address issues by analysis and evaluation.
Exit Level Outcome 8: Individual and team work.
Demonstrate knowledge and understanding of engineering management principles and apply these to one’s own work, as a member and a leader in a team and to manage products.
Exit Level Outcome 9: Independent learning.
Engage in independent and life long learning through well-developed learning skills.
Exit Level Outcome 10: Engineering professionalism.
Comprehend and apply ethical principles and commit to professional ethics, responsibilities and norms of engineering technology practise.
Specific Outcome 3. Basic knowledge of the mining value chain.
Methods of exploration in the mining value chain
Remote sensing: use sensors to collect data of an object or an area without being in direct contact with it. These sensors can be on satellites or be placed on an aircraft. Examples of this method include: Geologic mapping; aerial photographs; satellite imagery and airborne geophysical data.
Geophysics: use measurements connected with physical properties made at or above the ground surface and in boreholes to obtain conclusions about concealed geology. Geophysical methods can be classified as passive (naturally existing fields) or active (fields generated by some stimulus). Geophysics exploration may be based on resistivity (measuring differences in specific gravity of rock masses), spontaneous polarization (measuring differences in spontaneous electrical potential caused by electrochemical reactions), induced polarization (measuring changes in double-layer charge within a mineral interface), magnetic susceptibility (measuring changes in structure or magnetic susceptibility in certain near-surface rocks), among other properties.
Geochemistry: use surface materials such as soil, till, or vegetation that can be examined for identifying geochemical variations. Regional geochemical exploration has traditionally based on top soil or water stream sampling. Also, there may be a connection between the availability of some chemical elements and the existence of certain mineral resources.
Pitting and trenching: use shallow excavation for deep sampling material. They also provide progressive exposure of material facilitating localized geological interpretations.
Drilling: use material extracted from a small diameter hole. Several methods are available according to different objectives, ground conditions and cost (e.g. auger drilling, percussion drilling rotary drilling etc.).
What is Beneficiation?
Beneficiation any process that improves the economic value of the ore by removing valueless mineral which results in a higher-grade product and a waste stream.
Mining process: a large artificial freshwater pond is produced in the dunes on which floats the dredger and concentrator plant. While the dredge removes the material from the front end of the pond, the waste generated by the separation process is stored at the back. As a result, the pond progressively moves in a forward direction. Burrowing into the face of the dune, the dredger moves at a rate of two to three metres per day, depending on the height of the dune. The sand face collapses into the pond forming slurry as it is undermined, which is sucked up and pumped to a floating concentrator. At this point, the heavy minerals are separated from the sand by exploiting differences in mineral density through a multi-stage circuit of sluices. A portion of the magnetite and the chromium-containing minerals are removed magnetically, and the resulting heavy minerals concentrate (HMC) is stockpiled for transportation by road to the mineral separation plant.
Mineral processing: upon arrival at the mineral separation plant, located at the smelter site, the heavy mineral concentrate is re-slurred and pumped into the feed preparation circuit. The slurry here is passed over successive stages of low and high intensity magnets to remove the ilmenite that is set aside as feedstock for the smelter. The non-magnetic materials, including zircon and rutile, are concentrated for further processing in the dry mill. These two minerals are separated and upgraded in a series of circuits comprising a number of stages of high-tension electrostatic separation, magnetic separation, gravity separation, and screening. Essentially, rutile and zircon are separated by their difference in conductivity with residual gangue is removed by magnetic and gravity separation circuits. At this point, the zircon and rutile can be dispatched and sold in their raw form as mineral sands. Some zircon is upgraded to produce a higher-grade product by removing various impurities.
Roasting process: Ilmenite, as mined, has a high Cr2O3 content which makes it unsuitable for direct smelting to Titania slag. Some of this Cr2O3 is removed at the mine when the ilmenite is passed through a magnetic separation step in which the highly susceptible Cr2O3 rich fraction of the ilmenite is removed. The remaining minerals containing Cr2O3 are not readily separable from the ilmenite by magnetic means as their magnetic susceptibility is almost identical to that of ilmenite. The separation is therefore affected by subjecting the ilmenite to an oxidizing roast that alters the magnetic susceptibility of the ilmenite while leaving Cr2O3 containing minerals unchanged. The roasting process is carried out in two-three stage fluidised bed roasters operated in the temperature range of 730°C to 800°C. after being roasted and cooled to ambient temperature, the roaster product is passed over low-intensity drum magnets to separate out the now, more magnetic low-chromium fraction of ilmenite, yielding a feed material suitable for the smelter. Anthracite is dried on two Peabody grate-type units to produce a reductant for the furnaces. A portion of the reductant is screened out for use as a re-carburising agent for the iron.
Smelting process: the TiO2 content is increased by smelting the ilmenite with anthracite to produce a slag containing approximately 85 percent titanium dioxide and a high purity, low-manganese pig iron as a co-product. The process generates very little in the way of waste products. The ilmenite is partially reduced with char to yield a low-manganese iron, a slag containing 85 percent TiO2 and a gas containing roughly 85 percent CO and 12 percent H2 according to the reaction: FeTiO3 + C = TiO2 + Fe + CO. the gas is cooled, scrubbed, pressurised, and used around the site as a fuel for heating and drying. Any excess smelter gas is burnt in a flare stack. The small of dust that is scrubbed from the furnace off-gas is the only discard produced. No fluxes are added to modify the slag properties such as density, fluidity, melting point, or electrical conductivity, because this would dilute the Titania in the slag and more reductant would be required to provide the required degree of reduction to yield the 85 percent Titania tapped slag. The slag produced is highly aggressive towards the furnace refractories. For this reason, control of the thermal balance is essential, with the furnace being operated to form a protective frozen layer of material along the side and end walls of the furnace. These furnace products are further upgraded in subsequent processes. The titanium oxide slag is crushed and classified according to particle size and sold largely to pigment manufactures.
Slag and iron processing: upon the receipt of the iron ladle at the iron processing plant, the ladle is weighed and the iron temperature taken with a dip thermocouple. The ladle is placed on a ladle tilter and an injection hose connected to an angled tuyere in the ladle hood. Nitrogen is fed through the tuyere and the ladle tilted until the tuyere is suitably submerged. Injection reagents are then fed sequentially into the nitrogen stream until processing is complete. As a general rule, the more stringent quality iron grades are produced from the larger taps of hot iron. On completion of the injection process, the iron is cast into pigs on a twin strand pig-casting machine. Several grades of iron are produced, and individual heats are either stockpiled on site or loaded onto rail cars for transport to Richards bay harbour or to customers in south Africa. The cooled slag is crushed and then ground and dried in an Aero fall mill. The mill product is classified to produce the size fractions required by the chloride and sulphate slag markets. The slag is then stored in silos ready for dispatch by rail to the harbour or to the local customer.