Quiz 1 Flashcards
Surface Mining Techniques : Name the 7 types of surface mining?
- Open Pit
- Strip Mining
- Quarrying
- Highwall (Auger)
- Mountaintop
- Placer
- Solution Mining
Surface Mining Techniques : For which type of geological deposits are open pit mostly used
- vein type
- disseminated metallic ores (hard rocks)
- erratic stratigraphic units
Surface Mining Techniques : In open-pit when does reclamation start?
Until almost all ore production is completed
Surface Mining Techniques : What are the advantages (2) and disadvantages(3) of the conventiional pushback
A:
1. allows to perform larger areas
2. more flexible and less complicated road design
D:
1. NPV to be generated will be less
2. less flexibility in scheduling operations
3. less opportunity to blend ores
Surface Mining Techniques : What pratice is shown here?
Sequential Pushbacks
Surface Mining Techniques : What characteristics is strip mining ideally applied to?
- relatively horizontal (tabular)
- bedded
- shallow
- uniform
- Continuous
Surface Mining Techniques : What is the main indicator of performance for strip mining?
stripping ratio (tonne of waste rock per tonne of ore)
Surface Mining Techniques : In what are strip mine is typically divided into?
long rectangular blocks (sometimes referred to as panels) that are mined in sequence
Surface Mining Techniques : Name main characteristics 3 of strip mining?
- Production rates are high (economies of scale)
- Safety is high
- excavation and loading can be conducted in a continuous way
Surface Mining Techniques : What is contour mining?
Strip mining narrow zones in a mountainous terrain
Surface Mining Techniques : Name the 3 types of contour mining?
- Haulback
- Box-cut
- Blockcut
Surface Mining Techniques : Describe haulback contour mining.
overburden material is hauled by trucks and placed directly in the void created by the removal of coal. Highwalls are eliminated and near original surface is restored
Surface Mining Techniques : Describe box-cut contour mining.
Box-cut or terrain is created through overburden to access to seam. This
box is extended along with strike direction
Surface Mining Techniques : Describe block-cut contour mining.
In this method, overburden blocks, which are wider than 20 m, are removed as
a unit and disposed in mined-out voids.
Surface Mining Techniques : Why do we want keep the stripping ratio as constant as possible?
Since equipment and coal processing unit have constant capacities, a change in stripping ratio will cause capacity utilization issues.
Surface Mining Techniques : Give the break-even Stripping Ratio formula.
Surface Mining Techniques : Give the overall Stripping ratio formula.
Surface Mining Techniques : Name the 2 types of Quarrying activties.
- Aggregate mining (e.g., construction materials (gravel and sand))
- Dimension stone mining (e.g., marble, slate)
Surface Mining Techniques : Name the 5 factors affecting quarry selection since quarried material is cheap
- Large overburden removal cost cannot be paid off
- There should be sufficient reserve
- There should not be a dewatering cost
- Resource should be close to the market
- Environmental problems should be kept in minimum
Surface Mining Techniques : In Quarrying for Dimension Stone how is the Rock is cut (6) ?
- Diamond wire saw
- Jet burning
- Diamond saw blade
- Laser cutting
- Water jet
- Drilling and blasting
Surface Mining Techniques : What the 2 Criteria used for sawability?
- Cutting or production rate of stone blocks and slabs in m2
/h. (determined by rock properties) - Wear rate of diamond tools
Surface Mining Techniques : When is Auger and Highwall Mining used?
When contour strip mining has been completed and the removal of overburden to access additional coal no longer becomes economically feasible
Surface Mining Techniques : What is the most challenging part of mountain top mining?
the development of roads to access the areas that will be mined
Surface Mining Techniques : Name envionmental downsides of mountain top mining (3)?
- Mined area cannot be reclaimed or restored to original ground in an easy way
- Clearing before blasting leads to removal of trees and vegetations
- It causes biodiversity loss and adverse effect on water quality
Surface Mining Techniques : What is a placer?
Placer is a gravel deposit in heavy minerals, especially gold particles and gemstones
Surface Mining Techniques : What is placer mining?
Placer mining comprises various mining methods using water to recover valuable ore from the surrounding sediment
Surface Mining Techniques : Name 2 types of placer mining.
- Hydraulic mining
- Dredging mining
Surface Mining Techniques : What is Hydraulic mining? Where is used?
Powerful jet of water to dislodge minerals present in unconsolidated material.
Concentration from the tailings of old mines
Surface Mining Techniques : On what depends the application of Hydraulic mining (3)?
- availability of water,
- the amenability of the rock to be slurried
- pumpable.
Surface Mining Techniques : Name 4 types of dredge mining equipment. 2 types for last
- Draglines & Backhoes
- Bucket Wheel Dredge
- Suction Cutter Dredge
- Bucketline Dredge (Headline/Spud Dredge)
Surface Mining Techniques : What solution mining used for?
mining method used to recover minerals through boreholes drilled into a deposit.
Surface Mining Techniques : What are the 3 types of solution mining?
- in-situ
- heap
- tank
Surface Mining Techniques : What is in-situ solution mining?
The in-situ leaching involves drilling holes into the deposit and then injecting a
lixiviant or leaching solution to dissolve the orebody.
Surface Mining Techniques : When is in-situ solution mining used (2)?
- mineral processing is very expensive
- waste contains low quantity of valuable metal
Surface Mining Techniques : Name the steps of Heap Leaching solution mining (5)?
- Ore is crushed (>5 mm) and/or agglomerated
- It is stacked over an engineered impermeable pad
- It is wetted with lixiviant* (solvent) chemicals under atmospheric conditions
- Leachate (metal loaded solutions) is collected for metal recovery processes
- The solution is processed to recover the metals
Name the Two forms of Sample preparation method and Laboratory sampling procedures
- Coning and Quartering
- Riffling Method
Explain Coning and Quartering
Explain Rifling.
Explain accuracy and precistion
Accuracy: How close to the real value
Precision: Repeatable results
Define a Lot
the total collection of material for which an estimate of some component is required.
Define a Component:
the property that is to be estimated using a sample: e.g., grade, density,
moisture, etc
Define a Sample
the part of a lot on which a determination of a component will be carried
out, where each part of the lot had an equal probability of being selected into the
sample
Define a Specimen
the part of a lot on which a determination of a component will be carried
out, but for which the rule of equal probability of selection has not been respected
Define a Increment
the part or whole of a sample, selected from the lot with a single cut of
the sampling device. A number of increments may be combined to form one sample.
Name factors that cumulatively affect the precision of any assay result (4)
- the mass of material being assayed
- the homogeneity of the material being assayed
- the concentration of the component of interest
- matrix effects due to other elements in solution
Name the 7 steps of Shaw’s sampling protocol.
- one quarter drill core
- Jaw crusher
- Cone crusher
- Riffle
- Pulverizer
- Trowel
- Enveloppes
According to Gy The magnitude of sample preparation error is related to what (3)?
- Particle size
- Weight of subsample
- Mineralogical composition of ore being sampled
What is liberation?
It is an event that releases valuable mineral from unwanted minera
What is a bulk density?
A density that takes voids into account
Give the tonnage of block formula
The average bulk density may be called as a conversion factor. Why is it rarely appropriate to use a single conversion factor for an entire deposit.
The variations in mineralogy and physical character are significant throughout
a mineral deposit
Name methods for estimating bulk density (5).
- Archimedes-type measurements on whole core (in the field) or core or rock fragments
- Lab measurements of pulverized material (generally unsatisfactory in resource/reserve estimation
- Physical measurements for long lengths of whole core on-site (dimensions and weight)
- Stoichiometry based on whole-rock chemical analyses
- Gamma–gamma logging of drill holes
Suppose that the central part of a layered, massive sulfide deposit consists of 10 (vol)% sphalerite (s.g. = 4.0), 45 (vol)% pyrrhotite (s.g. = 4.6) and 45 (vol)% pyrite (s.g. = 5.1). What is the Bulk density?
Bulk density = 4.0 x 0.10 + 4.6 x 0.45 + 5.1 x 0.45 = 4.77
What does compation reflect?
Compaction reflects the decrease in volume of material from its blasted state to the
volume it occupies once it is placed on a dump or stockpile.
What is the swell factor of this?
What is the angle of repose
angle of repose is defined as the steepest angle at which unconsolidated material (e.g., blasted or crushed rock) can adapt without slumping when it is placed in a pile
2 parameters that increase/descrease angle of repose.
Increase:
1. Moisture content
2. Particle roughness
Decrease:
1. Size of the particles
2. Lifting velocity
What is the main source of error in an estimation?
The variability of the grades within the deposit
What are the sources of error or the factors affecting variability
1) Continuity
2) Range (Zone of influence or distance)
3) Structural and small scale variation
4) Degree of homogeneity
Explain range in factors affecting variability.
the influence of a sample extends for a certain distance. After this distance, this sample has no effect on estimation
Name the 3 Sources of small scale variation.
- Geological structures which are smaller than the sampling grid
- Random phenomena such as weathering
- Sampling and data preparation errors
Explain Structural variation in factors affecting variability.
It refers to the variation associated with geological structures which are
larger than the sampling or drilling grid.
Explain Structural variation in factors affecting variability.
the estimation error may vary with changes in geological conditions. The degree of homogeneity may depend on direction
The semi-variogram provides information about 4 things.
- Zone of influence or range
- Continuity
- Structural and small-scale variation
- Anisotropies
What are the 4 Semi-variogram parameters
- Nugget effect (C0)
- Sill (C0 + C1)
- Range
- Anisotropies (when generate for different directions)
Compute weights using inverse distance weighted interpolation
