Opencast Mining MCQs Questions & Answers | Mining Engineering

The correct answer to this question is D, Electric.

Permanent and semi-permanent machines, such as electric shovels, drills, and haul trucks, are always powered by electricity. They are typically connected to the power supply system of the mine or a nearby substation through cables and conductors.

Electric power is preferred over other types of power sources, such as diesel or kerosene, for several reasons. Electric power is cleaner, more efficient, and more economical than other types of power. Electric machines also produce less noise and air pollution, making them more environmentally friendly.

Electric power can be generated from various sources, including coal, natural gas, nuclear, hydro, and renewable energy sources such as solar and wind power. The choice of power generation depends on several factors, including availability, cost, and environmental impact.

Therefore, the correct answer is D, Electric.

The requirements of an electric power supply system in surface mines are:

A. Adequate capacity: The power supply system must have sufficient capacity to meet the electrical demands of the mining equipment and facilities.

B. Safe: The power supply system must be designed and maintained to ensure safe operation, with appropriate protections against electrical hazards.

C. Required voltage and frequency: The power supply system must provide the voltage and frequency required by the mining equipment and facilities.

D. Economical: The power supply system must be designed and operated in a cost-effective manner.

Therefore, the answer to this question is Option E, All these.

A motor that improves power factor is a Synchronous motor (over excited). Power factor is the ratio of real power (measured in watts) to apparent power (measured in volt-amperes). A motor with a low power factor draws more current than is necessary to perform the desired work, which results in higher energy costs and lower system efficiency. By contrast, a synchronous motor with overexcitation can correct the power factor by adjusting the amount of reactive power that it draws from the power grid.

Option A, Induction motor, and Option B, Slip ring motor, do not have the capability to adjust the power factor.

Therefore, the answer to this question is Option C, Synchronous motor (over excited).

The diameter and depth of blast holes are generally kept constant depending on the size of equipment. In surface mining operations, the size of the equipment used for drilling blast holes determines the size of the blast holes that can be drilled. The diameter and depth of the blast holes must be sufficient to accommodate the explosive charge and ensure that the blast is effective in breaking up the rock mass.

Option A, Base, Option C, Length, and Option D, Highwall, are not directly related to the size of the equipment used for drilling blast holes.

Therefore, the answer to this question is Option B, Size.

Machines using crawler chains are not allowed to cross public roads if they possess Cleats or Grouser plates. Cleats or Grouser plates are metal protrusions that are mounted onto the crawler tracks of heavy machinery to provide better traction and stability on uneven surfaces. However, these plates can cause significant damage to public roads and are therefore not allowed for use on machines that need to cross public roads.

Option B, Smooth grouser plates, and Option C, Plain plates without rubber, do not have protrusions that can cause damage to public roads and are therefore allowed to be used on machines that need to cross public roads.

Therefore, the answer to this question is Option A, Cleats or Grouser plates.

A Ripper is essentially a crawler-mounted attachment used in surface mining and construction operations. The ripper attachment is designed to break up and loosen hard soil and rock, allowing for easier excavation and removal.

Option A, Tyre, and Option C, Wheel, are not typically used for ripper attachments as they are not stable enough for heavy-duty excavation work.

Therefore, the answer to this question is Option B, Crawler.

C.S.R stands for Corporate Social Responsibility. This refers to the concept that companies have a responsibility to operate in a way that benefits society, the environment, and the economy, while also maximizing profits. Corporate social responsibility involves taking into account the impact of a company's operations on the community, the environment, and other stakeholders, and working to minimize any negative effects and promote positive social and environmental outcomes.

Option A, Company Survey Reportability, and Option C, Central Security Reason, are not related to the mining industry or corporate social responsibility.

Therefore, the answer to this question is Option B, Corporate Social Responsibility.