Bulk materials and evaporites (part 2) Flashcards
What are fillers?
Chemically inert fine materials
Why are fillers used?
Added to provide bulk or to modify properties:
Weight
Toughness
Opacity
What are Barytes used as?
Industrial material but alos as a source of Barium
What are the properties of Barytes?
Heavy, non-abrasive, inert, non-corrosive, insoluble, non-toxic, high adsorption capacity for hard radiation
What are barytes ideal for mining?
Mud drilling as borehole lubrication
What is the global distribution of Barytes deposits?
Deposits found throughout world in a variety of geological environments
What are the three main types of barytes deposits?
stratiform, vein and residual
What industry are silicates a major part of?
The glass industry
What are the sourcess of glass made from silica?
Usually sources from crushed sandstone or pure beach sands
What are the properties of silica?
High melting point of quartz (1713 ̊C) and high viscosity when molten
What other elements can be added to silica to provide additional properties?
Soda
Lime
Alumina
Boron
Lead
Why is soda used in producing glass from silica?
lowers melting temperature (as low as 500 ̊C) but soluble
Why is lime used in producing glass from silica?
stabalising element and reduces solubility
Why is alumina used in producing glass from silica?
Increases chemical resistance
In larger quantities used for fibres and cooking utensils
Why is boron used in producing glass from silica?
resistant to corrosion and heating and cooling (pyrex)
Why is lead used in producing glass from silica?
for crystal tableware
How is glass coloured?
By the addition of mineral oxides
Why is blasting used?
to fragment competent rock or
to detach large blocks
What 2 primary methods are used to remove dimensional stone?
Drilling
Jet piercing
What is the process of drilling for dimensional stone?
vertical holes drilled about 3 cm apart to the desired depth (up to 7 m). Blocks then levered out or have secondary drilling
What is the process of jet piercing for dimensional stone?
high-velocity 4,000 degree flame directed at the rock to be removed, causing a continuous flaking action. As the flame nozzle is moved back and forth, a deep channel is created.
How is the process of blasting carried out?
drilled holes filled with explosive
(Ammonium Nitrate Fuel Oil (ANFO)
What is primary blasting?
working back faces, typically weekly and producing 15,000-20,000 tons per blast
What is secondary blasting?
more frequent, cleaning
up the working face and shattering large rocks.
What are quarry benches?
In hard rock quarries a series of layers in which the quarry is worked from top to bottom because the deposit is usually thicker than can safely be worked as one quarry face.
What sizes is the typical quarry face?
Quarry faces rarely > 15 m; in UK special assessments required if faces exceed this
Why is the width of quarry benches important?
Acts as protection for the lower levels of the quarry
Why is bench width important for the design of the final slope?
Access for restoration activities
Access ramps to the quarry floor
Feasibility of backfilling, or tipping loose material onto the bench
Feasibility of rock-fall protection measures
What is becoming the most common width for quarry benches?
8-12 m
What is the bench height determined by?
Width, strength and reach of equipment
What are the production volume figures linked to quarrying?
300Mt/yr
How much off the 300 million tons a year comes from sand and gravel?
120mt/yr (80% land extraction)
What is the average uk demand for aggregates for road construction and repair per year?
50-80 million tons
What is the majority of uk demand of aggregates for road co friction and repair for?
Crushed road stone
What 2 types of crushed road stone are wanted by the uk construction sector?
–Compacted aggregate for lower road layers
–Crushed aggregate bound in bitumen or cement for surface layers
Why is recyling of aggregates done and what is the limiting factor of this?
Reduce cost, environmental impact and increase sustainability but this has an effect on quality
What are the layers of road from top to bottom?
Surface dressing
Surf course
Base course
Sub base
Capping layer
Top 3 bitumen bound
Bottom 2 compacted, unbound
What is the purpose of the road surface layer for roads?
Dressing, surface course and binder course
Primarily to provide skid resistance and drainage
High Specification Aggregate (HSA)
What is the purpose of the base layers in road construction?
Base course, sub base, capping layer
provide strength and stability, to raise level, and to improve underlying groumdconditions
Not necessarily HSA
Why might high specification aggregate (HSA) be used?
remedial treatment
to prolong the life of the skid resistant surface