Mining Engineering Exam 3

-Mines are broadly classified into which two main, overarching groups

a) Surface mines and underground mines

-According to the slides, what percentage range of all currently operating metal mines are classified as surface mines

a) Less than 50% of all currently operating metal mines

-Which two primary materials are extracted and come directly out of the open pit itself

b) Ore, which is the commodity, and waste rock

-In the context of open pit mining, what is the correct definition of “ore”

c) The rock that contains the commodity of interest

-What is “waste rock” in an open pit mining operation

d) Zero or very low grade rock that must be removed to access the ore

-What are the two main types of output produced by the processing plant in an open pit mine operation

a) A marketable product and tailings

-Which definition accurately describes “tailings” in an open pit mine

b) A waste product that results from the processing the ore

-The facilities for storing waste rock and tailings are designed to meet which essential criteria

c) Facilities designed to be operational and stable for the life of the mine and after the mine closes

-The open pits on the Mesabi Iron Range in Minnesota primarily mine which specific type of ore deposit

b) Taconite

-The Bingham Canyon mine is a prominent open pit operation mining which commodity and where

c) A copper mine near Salt Lake City, Utah

-In which geographic region is the large Chuquicamata copper mine located

a) Atacama desert, northern Chile

-The Betze-Post open pit mine is an example of a mine for which commodity and is located in which state

d) The gold open pit mine in Nevada

-Which components are specifically noted to be part of the Highland Valley Copper Mine site layout

c) Three pits, waste rock piles, a process plant, and a drainage collection pond

-What is the main objective of open pit mining regarding reaching the ore body

d) To get to the depth where ore is as quickly as possible

-To minimize costs and time, what is the desired characteristic for open pit slopes

a) Pit slopes should be as steep as possible to minimize costs and time

-Why can rock slopes in an open pit not be made arbitrarily steep

b) Most rock masses are not strong enough to stand if the slope is too steep

-Safe overall slope angles for an open pit excavation typically range within which values from the horizontal

c) Typically range between 35 and 45 degrees from the horizontal

-Decreasing the overall angle of an open pit in only one degree can have what major consequence, as illustrated by the conceptual exercise

d) Can impact significantly the cost of moving waste rock to access ore at depth

-How is the overall open pit slope angle, as shown in the benched pit slope photograph in the slides, typically measured

c) The angle is measured from a horizontal line

-The slides mention that the average slope of an open pit mine, when viewed as a whole, is approximately how many degrees

a) approximately 30 degrees

-The stability of the slopes of an open pit mine is primarily a problem related to which field of engineering

a) Geotechnical engineering

-For safety, it is imperative that which types of slope failures do not occur

b) Rockfalls, large boulders falling, and extensive rock slides involving large quantities of rock

-Why are stabilization measures like rockbolts, cables, and wire meshes not generally used for open pit slopes

b) They are ineffective in the massive rock masses found in large open pit mines

-What is the primary solution to constructing stable slopes while still maintaining a steep overall angle in an open pit mine

a) Excavate the slope in steps or benches

-What is the typical height range for benches in an open pit mine

c) About 10 to 30 m, or 33 to 98 ft high

-How are the slopes of the individual benches designed, compared to the overall pit slope angle

c) They are designed to be much gentler, typically less than 30 degrees, to aid stability

-Regarding slope failures, how do the benches contribute to pit safety

a) Slope failures will occur, but their extent will be confined to the immediate bench area and the failed rock mass will be caught by the bench

-Pit slopes are closely monitored for signs of significant movement using which technology described in the slides

b) Laser reflection from prisms mounted in the slope or radar equipment

-If water is suspected to be the cause of significant slope movement, what is the stabilization method normally employed

d) Drainage holes

-What term is used to describe the pit widening that is necessary to maintain a stable slope angle as the mine gets deeper

c) Pushback

-The strip ratio is a key metric in open pit mining, defined as the amount of waste that must be removed per unit mass of ore. What is its mathematical form

a) mass of waste / mass of ore

-What is the fundamental definition of mineral exploration, according to the course slides?

The search for mineral concentrations that are high enough to be profitably extracted and processed

-Which of the following mineral exploration methods is categorized as having the lowest cost per unit area?

Geological mapping that includes fieldwork and analysis of bedrock exposures

-What is the main driving reason for a mining company to continuously engage in mineral exploration?

To find more tons of ore to replace the material it currently extracts to remain in operation

-What is the main alternative to mineral exploration for a mining company looking to acquire new ore reserves?

Acquisition of other mining companies that already possess mineral rights to known quantities of ore

-What is considered an important prerequisite for successfully locating new ore deposits?

Understanding the local geology and the manner in which the deposits could have originally formed

-Which geological term refers to a crustal block or fragment that has a distinctive geological history different from its surrounding areas and is typically bounded by faults?

A ‘terrane’ which is preserved geological history usually bounded by distinct fault lines

-When geologists examine satellite images in remote sensing for mineral exploration, what change is of primary interest to them?

Changes in the pseudo-color that might suggest the presence of key geological features like faults

-What is the main feature that satellite imagery in remote sensing allows geologists to initially identify?

Geological features, such as folds and major fault systems, that could indicate mineral concentration

-What is a key characteristic that defines a topographic map?

It is a type of map that provides a detailed and quantitative representation of relief using contour lines

-What is the primary task of geologists when performing geological mapping after a favorable area has been identified?

To go into the field and map the bedrock exposures, or outcrops, to find spatial relationships

-What is a more likely indicator of an ore deposit for a geologist in the field, rather than the actual economic mineral itself?

Minerals that are associated with the magmatic or hydrothermal activity that formed the deposit

-What are structural controls in the context of mineral exploration on a geologic map?

Features like faults or folds that had a controlling influence on the location of the mineralization

-In geophysical surveys, what is the term used for the changes in physical properties of the ground that are being searched for by the instruments?

Anomalies, which are changes in physical properties such as the earth’s magnetic or gravity field

-Which of the following is NOT one of the common physical properties analyzed in geophysical surveys, according to the slides?

The physical strength or hardness of the rock mass, which is a mechanical property

-How does the presence of metals in a rock body typically affect the physical properties measured by a geophysical survey?

It will alter the local intensity of the earth’s magnetic field and change the ground’s response to a radio signal

-How can a large body of relatively light rock be identified using a gravity survey?

The force of gravity over the light rocks would be measurably less than the force over surrounding denser rocks

-From which location or setup can geophysical surveys be conducted to collect their required data?

From either an airplane or other airborne platform, from the ground, or a combination of both locations

-On an airborne magnetic map, what does the warm color (red and purple) representation typically indicate?

An area with a high magnetic signature, suggesting the presence of magnetic minerals in the rock

-On a geophysical map, what do linear magnetic lows (often shown with white dashed lines) sometimes represent an interpretation of?

Major fault zones, some of which may correlate with known mineral showings in the area

-What is the fundamental ‘big picture’ concept behind conducting a geochemical survey for mineral exploration?

To detect metals leached by groundwater and deposited in overlying soil, streams, or plant life

-In a geochemical survey, how are anomalous high concentrations of metals typically measured?

They are measured using relative values compared to a fixed regional baseline value or average

-What is the main, single purpose of undertaking a large-scale drilling program in mineral exploration?

To obtain physical core samples of the rock mass that can be chemically analyzed for mineral concentration

-In core drilling, how is the cylindrical stub of rock (the core) formed and recovered?

A diamond drill bit grinds the rock as the pipe is rotated, and the stub breaks off and enters a core barrel

-What material is commonly used for the tip of cylindrical drill bits in diamond drilling, giving the method its name?

The drill bit tip is made of hardened steel with diamond inserts, which are extremely resistant to abrasion

-What is the approximate internal diameter of the rock core produced when using a common ‘N’ size diamond drill bit?

The internal diameter is approximately 54 millimeters, which is about 2 inches in cross-sectional diameter

-What is the term for the process where geologists meticulously look at each drill core sample to identify economic minerals, alterations, or other indicators of an ore-forming system?

The investigation process that is commonly referred to as core logging, which is a visual inspection

-After a core sample has been sawed into halves or quarters, where is one of the parts of the core sample sent for detailed analysis?

It is sent to an assaying lab for chemical analysis or for detailed mineralogical analysis using a microscope

-Which description accurately characterizes the material recovered during Reverse Circulation (RC) drilling?

Rock chips are forced up the double-walled pipe by compressed air and collected in a bin for sampling

-What is the main disadvantage that makes Reverse Circulation (RC) drilling less reliable for mineral exploration on its own, compared to diamond core drilling?

The source of the collected rock chips is not always accurately known, leading to potential inaccuracy

-Which drilling method is a cheaper alternative and is typically used to verify the results obtained from a more accurate drilling method?

Reverse circulation drilling, which collects rock chips and has a lower cost per meter drilled

-In mineral exploration, which drilling method is characterized as being the most time-consuming and expensive, but provides the most accurate spatial distribution of metal concentration?

Diamond core drilling, due to the precise location of the core sample and the effort required for recovery

-What is the primary goal that the entire drilling campaign is designed to achieve in the overall exploration process?

To define an accurate three-dimensional ore-body model, which is the basis for the design of the mine

-Once the ore-body model is defined, what is one of the most critical uses of the chemical analysis results (assays) of the drill cores?

To develop a detailed three-dimensional model (also referred to as ‘block model’) of the ore body where colors denote the grade or property

-In the context of mine planning and design, which component is defined by using the concentrations of metal (grades/assays) from drill cores to define blocks where the grade is assumed constant?

The block model, which is the fundamental basis for the mine planning and design process

-Given a fully developed block model, what is one of the key tasks that can be devised using this model?

A mining sequence of ore blocks that is specifically designed to maximize the revenue obtained

-In a block model used for mine planning, what property is assumed to be constant within the volume of each individual block?

The concentration of metal (or grade), which is derived from the chemical analysis of the drill cores

-In the sequence of mineral exploration methods in the slides, which is shown as having the highest cost per unit area of exploration?

Bulk sampling and diamond core drilling, which are the most invasive and time-consuming steps

-What is the fundamental material extracted from an underground mine, as stated in the slides?

d) Only the ore body itself is extracted, with minimal other rock materials

-What is the term used for the waste material produced as a result of sinking the main shaft and driving the tunnels to access the ore body?

a) Development waste, which is sometimes utilized as a crucial backfill material within the mine

-Underground mines are primarily used to exploit which type of ore deposit?

d) High-grade, deep ore bodies, where open-pit mining is no longer economically viable

-Which design issue is explicitly listed as a significant design issue for an underground mine, alongside geometry and materials handling?

c) The ground support necessary to maintain the stability of all the underground openings

-For a large-capacity, highly mechanized underground mine, what is considered a typical, substantial mining rate (excluding block caving)?

b) A significant rate of 10,000 metric tons per day (t/d) or greater

-What is the approximate critical limiting depth below which underground mining would always be preferred over open-pit mining due to stability and hauling cost issues?

d) A depth of 1,000 meters (about 3,300 ft) where slope stability and haulage costs become excessive

-Which of the following is defined as a vertical or inclined passageway used for access from one level or drift to another (usually upward)?

a) A Raise, which allows for the movement of personnel and equipment to different working areas

-What is the term for a horizontal passageway driven along the length of the ore body for access and mining purposes?

b) A Drift, which runs parallel to the strike or long dimension of the mineralized rock

-What is a Crosscut specifically defined as in the anatomy of an underground mine?

c) A horizontal passageway that is driven for the purpose of access to the ore body from the shaft area

-What is the purpose of the Decline or Ramp system in an underground mine?

c) It is a spiral or inclined passageway used for the purpose of access from one level to another in the mine

-In the anatomy of an underground mine, what is a Stope?

d) An opening from which the ore is mined, which can be a variety of different shapes and sizes

-What is the key distinction between the Hanging Wall and the Footwall of a dipping ore body?

b) The Hanging Wall is the rock above, while the Footwall is the rock below the dipping ore body

-The designation of Levels in an underground mine is typically based on what measurement?

a) The elevation from some arbitrary datum, such as the “2300 level” designation

-What component of an underground mine is defined as a subvertical chute designed for the transfer of broken ore between different levels?

b) The Ore Pass, which facilitates gravity-driven movement of material to a lower haulage level

-What is the initial, primary function of a Winze in underground mine development?

a) To be constructed as the beginning stage of a Raise, driven down from an upper level

-What is the primary purpose of the Headframe in a shaft system?

c) To contain and protect the sheaves and hoisting mechanism located directly above the main vertical shaft

-Before personnel and equipment are allowed to enter an underground working area, which two essential services must be available and functional?

c) The necessary ventilation and power systems must be established and fully operational

-What is the typical advance rate mentioned in the slides for a conventional, non-mechanized shaft construction?

c) A slow but steady rate of approximately 4 to 5 meters (13 to 16 ft) per day during normal operations

-To prevent instability or excessive water inflows during the construction of a shaft, what unique method can be employed?

c) Freezing the water by circulating refrigerants like brine through vertical pipes to form a stable ring

-What diameter is considered to be a small shaft, according to the provided information?

a) A diameter of 3 to 6 meters (about 10 to 20 ft) in its final, completed dimension

-Which of the following is NOT listed as one of the most common underground mining methods in the slides?

d) Narrow vein mining, a method used for very small and highly selective ore bodies

-What is the ultimate factor that primarily determines the choice of one underground mining method over another?

d) The overall economics of the operation, which includes both capital and operating costs

-Cut-and-fill mining is applied to ore bodies with which two primary characteristics?

b) Near-vertical ore bodies found in soft, low-strength sedimentary rock layers

-How is the ore typically removed in Cut-and-Fill mining?

b) It is removed in horizontal slices, starting from a bottom undercut and then advancing upward in sequence

-What material is used to back fill the void after a stope is mined out in cut-and-fill mining?

c) Tailings (sometimes with cement added to form a paste) that are allowed to drain to form a solid surface

-What two functions are served by the back fill material in the Cut-and-Fill mining method?

c) To support the stope walls and to provide a working platform for the equipment on the next slice

-Why is Cut-and-Fill mining described as a relatively expensive method?

c) It requires a significant amount of drilling, blasting, and moving the fill material for the entire process

-What is a key characteristic of the ore bodies to which Narrow Vein Mining is applied?

b) They are very narrow (as small as 0.5 m wide) and contain high-grade precious metals

-How is selectivity achieved in Narrow Vein mining to avoid mining waste rock?

b) By using blasting to “cut” a drift into the rock very close to the vein boundaries surgically

-Stoping is a method used for steeply dipping ore deposits in rock masses that possess which two characteristics?

c) Strong rock masses with regular boundaries between the economic ore and the host rock

-In Longhole Stoping, what is the primary difference that leads to it requiring less drilling compared to Sublevel Stoping?

b) Longhole Stoping utilizes longer (about 100 m) and larger-diameter blast holes for production

-What is the material used to back fill the stopes in longhole and sublevel stoping to allow for the recovery of the ore between the stopes?

b) Consolidated tailings, which enables the recovery of the ore from the crown pillars for high recovery