Bulk materials part 1 Flashcards
What represents the largest volume of earth materials extracted?
Building materials
What is the typical value of natural rock?
Low
What processes can be done to natural rock to add value?
Crushing
Cutting
Shaping
Calcining
What is the cheapest and most expensive rocks extracted in dollars per metric ton?
Cheap - Crushed stone ~$6
Expensive - slate ~$660
What is a dominant control on the cost of earth materials?
transport costs
What is the £/tonne km of different transport methods?
Lorry - 0.1
Rail - 0.04
Barge/ small ship - 0.016
Large ship - 0.002
Very large ship - 0.001
What are the positives of transporting by lorry?
Flexible
Small frequent loads
What problem is associated by transporting material by rail?
Limited to rail
What problems are associated by transporting materials by barge/ small ship?
Canal or coastal sites only
What transport problems are associated with large and very large ships?
Need deep water and special loading facilities
What different things can quarried stone be used for?
Rough construction
Rip-rap
Ashlar
Cut stone
Monumental stone
Flagstone/ paving
Slate
Terazzo
Crushed aggregate
What is the rough construction use of quarried stone?
Large blocks of rough hewn stone used for sea wall cores, bridge works and any other density filling usues
Finer mateiral for wall faces
What is the rip-rap use of quarried stone?
Large irregular shaped block (70-700kg)
Weighted supported stones for embankements, coast and river protection
What is the ashlar use of quarried stone?
rectangular bulding stone of non uniform size
What is the cut stone use of quarried stone?
Dimensional stone with textured surface
Can be thin veneers
What is the monumental stone use of quarried stone?
elaborate monuments
What is the flagstone use of quarried stone?
road construction and exterior flooring
What is the slate use of quarried stone?
Dressed roof tiles or mill stock slate
Small volume for snooker tables, lab surfaces or switch backs
What is the terazzo use of quarried stone?
Small chipped soft rock in cement for flooring / polished for smooth surface with lacing joins
What are the main attributes of building stone?
Apperance
Strength
Durability
Jefferson 1993
What did Robertson (1982) classify the attributes of bulding stone to be?
Hardness (H)
Elasticity (E)
Strength (S)
Permeability (μ)
Bulk density (Þ)
Linear thermal expansion (α)
Diffusifity (k)
How is hardness of bulding stone measured?
Moho scale
How is elasticity of bulding stone measured?
Youngs modulus
How is strength of bulding stone measured?
uniaxial compressive strength
What is aggregation?
combination of density, porosity and permeability are different aggregtion measures of mineral grains and how fluids enter rock
What are the geological parametrs affecting thr use of building stone?
Apperance (colour/ texture)
Block size and shape
Lateral and vertical variability
Fractures - faults, joints
Heterogenous vs homogenous
Frost susceptability
Presence of reactive minerals
Cementation
Weatherings rates
Clay content
Colour/ colour chnage
What are the three broad catergories for the causes of building decay?
Chemical
Physical
Biological
How can building stone be physically weathered?
Frost action
Thermal stresses
Attrition by pedestrians and vehicles along with wind blown particles
How can buidling stone be chemically weathered?
Atmospheric gas and liquid natural and man made
Soluble salts naturally in rock and created by humans (salt spreading)
How can buidling stone be biologically weathered?
Bacteria
Algae
Fungi
Lichens
Disruption by higher plants i.e., ivy
What is the problems associated with building stone for historic buildings with example?
Repairs and replacements from specific sites
Portland stone - finite production, low output, long backlogs
How can legal status affect the ulding stone usage in historic buildings?
Alternatives not permitted leading to high profile legal cases for a named stone
What are sand and gravel despoits in the UK associated with?
Concentrated in glacio-fluvial and marine sedimentary proceeses past and present most extensively on outwash plains and fluvial areas following quaternary glaciations
What triassic resource is there for sand/ gravel?
Triassic Bunter pebble beds crushed for use (remaining resources unconsolidated)
What is might mean sand is uneconomic when crushed from sandstone?
Unless there are specific properties (hardness, angularity, composition)
What are the most extensive uk terrestrial sequences of sand & gravel?
River deposits and terraces
How is the economic threshold for river deposits of sand and gravel decided?
Plot size and depth (typically >600mm)
How thick are the thickest uk gravels?
> 10m thick
What is left behind when gravel is extracted?
Tpically leaves basal 30-50cm which will be impure and mixed with underlying bedrock
Wh
What are terrestrial examples of sands and gravel?
Laterally varied potentially including muds/silts along with economically viable sand and gravel
What are terrestrial sands and gravels geographically constrained by?
Topographic highs and in channels, often in flat lying agricullturally productive areas
What is a marine example of sands and gravels?
Sands only
Well sorted by marine processes
How fast is extarction of marine sands?
Fast ~500 tons an hour
What is required of marine sands so that it can be used in construction?
Washing in freshwater
What are the drawbacks associated with excavating marine sand desposits?
Ecologically devestating and can remove heavy metals
What are terrestrial extraction techniques for sand and gravel?
Working at or below water table so potentially pumped dry
Face shovels/ excavators
Dragline
Bucket wheel excavator
Screening sieves
Sand and gravel conveyor
What are the advantages of face shovels/ excavators?
Low capacity
Versatile
Cheap
What factors needs to be considered when wanting to use a dragline to excavate sand and gravel?
medium capacity
less versatile than face shovels
Expensive
What factors needs to be considered when wanting to use bucket wheel excavators to extract sand and gravel?
Very high capacity
Very expensive
None present in UK currently
How are extracted sand and gravels transported for on site processing?
Truck or conveyor belt
How is material extracted and what is rejected when extracting sand and gravel?
Screens from coarse to fine with anything above 80mm being rejected
What might the screens for processing sand and gravel look like?
Pebbles 80-50mm
Gravels 50-20mm
Pea grit 20-5mm
Coarse sand 5-2mm
Fine sand 2-1mm
Fines (waste) <0.5mm
Private company cotswold 2021
What is the value of gravel at source?
1m3= 1.41 tonnes
Per ton value = £13.03
Extraction/ processing waste = 80kg per ton
What is the value of sand at source?
1m3= 1.52 tonne
value per ton = £16.21
Extraction/ processing waste = 50kg per ton
What costs are associated with extracting sand and gravel?
PLanning and site aquisition
Exvation costs (vehicles, fuel etc)
Environemtnal protection and pumping
Processing costs (grading, storing)
Labouor
Weighing and sale cost
Landscaping and restoration
What can diused excavation pits be used for?
Landfill
Recreational lakes
Ecological reserves
What is the difference between cement, mortar and concrete?
Cement - chemical binder
Mortar- cement mixed with sand
Concrete- cement mixed with sands and gravel
What are the ingredients of cement?
Limestone (CaCO)
Low amounts Fe, Mg, Mn
SHale or clay - alumina (Al2O3)
Shale clay or sand provides - silica
What are some occasional ingredients in cement?
Iron products
Gypsum or annhydrite
Why are iron products used in cement?
harden the cement faster
Why might gypsum/ annhydrite be used in cement?
controls setting time
What is the dominant ingredient in cement and how does this affect the location of cement works?
Limestone (10:1)
Cement works near limestone quarries
What are the steps in producing cement?
Mining limestone
Crushing and grinding
(Addition of iron and clay)
Griding and mixing
Roasting (1500c)
(gympus added)
Grinding
Packaged and shipped
WHat type of reaction is cement?
Water driven
What is produced in the cement reaction?
interlocking calcium and aluminiun crystals
WHat does cement bind with?
Porous materials upon contact
What is rebar?
Iron rods placed into cement for additional strength and support
What is the shelf life of cement?
Naturally set in 2-5 years (without water or damp)
What are clays?
Groups of fine grained, hydrated minerals with layer structure at the atomic level
What are some examples of clays?
Kaolinite ( China clay)
Hallosylite
Illite
Montmorillonite
Hectorite
Chlorite
Attapulgite
How do clays form when settling out of soulution?
Settling of fine grained patricles from suspension in low energy environments like lakes and pools
Relatively pure but often high levels of organics
Typically for construction
How do clays form from natural weathring?
Weathering of feldspars (typically in igenous)
Mineralogically pure (paper and ceramic production)
How do clays form from flocculation?
mixing of natural water bodies (estuarine)
Laterally variable
HIgh levels of reactive sulphur and maybe high bacteria levels
Not recognised source
What is ball clay?
Ultrafine particles which are easily cut and shaped
What is the difference between china and ball clay?
China coarser and not as malleable
How is china clay processed?
Washed from quarry by high pressure hose and flows to lowest quarry point
Slurry pumped to surface for processing
Kaolinite seperated by settling
Remaining slurry removed and dried
What are also removed by settling from the slurry when wanting clay?
heavier minerals like quartz and mica
What is the problem associated with large settling pools?
dangerous and hazardous
What are the uses of clay in the UK?
95% of all uk bricks
What problems are associated with using clay for bricks?
Transport limits value so usually locally sourced
What is the carboniferous mudstone and what are its uses?
Northern england and central scotland
Variable quality
Small amount brick suitable (too high in carbon and sulphur)
30% uk consumption for clay pipes
What are the uses of the Etruria formation? (clay)
Midlands
Carboniferous age
High quality (close to ideal brick clay)
MOstly used by clay roof tilers
What are the uses of the mercia mudstone group for clay?
Triassic age
Midlands
Mineralogy gives distinctive pale bodied housing/ engineering brick
What are some examples of uk brick clays?
Fireclays
Oxford clays
Weald and wadhurst clays
What ate the characteristics of the fireclays?
Carboniferous coalfields
Midlands and north uk
Produced in opencast coal extraction
Les than 7% uk consumption
High value (extraction cost and historic value)
What are the characteristics of the peterborough memeber ‘oxford clays’?
Jurassic age
Cambridgeshire/ Bedfordshire
High C content
Unusual manufacturing process (pressed bricks fired in kiln)
Production limited but historically important
What is the age and location of the weald and wadhurst clays?
Cretaceous
Southeast Endland
