week 6 + field trip Flashcards
Define mining
Commercial exploitation of mineral or energy resources. the extraction of material from the ground in order to recover one or more component parts of the mined material.
what is the difference between mineral processing and metallurgical extraction
processing is physically separating and concentrating ore minerals
metallurgical extraction aims to destroy the crystallographic bonds in the ore in order to recover the sought after element.
what forms of mineral processing are there
crushing, grinding, floatation, and gravity, magnetic and electrostatic separation.
what is a metal
elements which have characteristic chemical and physical properties like the ability to lose one or more electrons or the ability to conduct heat and electricity
what is a metalloid
elements with metallic and non metallic properties such as ability to gain electgrons
what is a heavy metal
metals with density greater than 6 g cm-3
what is common in metal ores
found in chemical combination with other elements forming metal bearing ore minerals such as oxides or sulfides.
what is the difference between ore minerals and industrial minerals
ore = minerals from which elements can be extracted at a reasonable profit
industrial = any rock or mineral of economic value excluding metallic ores, mineral fuels and gemstones. It has an industrial use.
what are the valueless minerals associated with an ore
gangue minerals
what characterises coal
dual porosity with fractures (cleats) which are larger than micropores. Methane is loosely sorbed on coal and can be released due to its permeability
what functions coal permeability
cleat number, connectedness and other minerals filling the voids.
what kind of hazards are associated with coal mining and what is involved in most coal mine disasters
rockbursts and methane explosions, suffocation. methane is involved in most of the disasters.
how much more potent is methane than CO2
28 times more.
what do we want to do with the methane
dont want to release it, its better to burn it. as an energy source it releases half the carbon as coal
where are most of the major coal seam gas exploration areas in australia
NSW and QLD
what is hydraulic fracturing (or fracking)
where water, sand and other chemicals are injected into a well that leads to the coal seam and creates fissures. natural gas flows out of the well at the top.
how much water is recovered in shale fracking
9-40%, always needs water because its dry.
what uses more water - shale gas or CSG
shale gas is a consumer of water
why do you use a cluster of piezometer
to determine the level of the different aquifers
what is flowback water
the withdrawn water following fracking. CSG produces the same or more of the same amount of water as was injected.
what is produced water
the residual water after flowback water is removed. the chemistry is natural and reflects the geological origins of the water
when is there a peak in stable production of gas
after the dewatering stage
what sort of disruption is associated with CSG
drill pads, haul roads, PW storage as well as devege, soil erosion and habitat loss
what risks are taken when pumping gas from CSGs
aquifer leakage and contamination of the groundwater by the hydraulic fracturing fluids.
what are some of the issues associated with produce water volume
evaporation (leftover brine)
discharge (what happens to small catchments, water tables or to the ocean?)
transporting it away (what happens elsewhere)
reinject brine
what level of TDS is suitable for livestock that uses produced water
<1000 mg/kg
what is characteristics of produced water
if you discharge sodium rich salts, you are increasing erodibility and erosion. having double charges ions doesn’t satisfies all charge points allowing more to stick to it (like clay).
can produced water be beneficial
yes, its different in each state
Queensland: water is used for the environment and users, as well as discharging
NSW: reuse and reinjection, treatment and resuse is approved on case by case
what are some treatment methods for re use of produced water
remove particulates, remove salt and disinfection
what is the preferred options for use of CSG water
aquifer reinjection, use of untreated water where no impacts would occur and appropriate treatment and reuse for agricultural, industrial and potable purposes.
what are non permitted options for use of CSG produced water
disposal via evaporation dams, to surface waters or to land
what are the two greatest environmental challenges for CSG water
salt and brine
