week 9 Flashcards
(19 cards)
what is stripping ratio
quantity of waste removed / quantity of ore uncovered
what cycle is mining
drill - blast - load - haul - dump
describe hydraulic shovels
- give greater precision mining but with higher maintenance costs
ore vs gangue minerals
ore minerals (i.e. valuable):
- chalcopyrite
- bornite
gangue minerals (i.e. unwanted)
- calcite
- magnetite
BC orebody requirements
- large > 50Mt
- sub-vertical orientation or thickness
- rock is weak enough to cave and fragment
- footprint large enough for ‘hydraulic radius’ for caving to initiate
- rock is strong enough to develop complex infrastructure below cave volume
- acceptable or relatively high grades at base of cave volume
describe cave monitoring by seismic activity
- instrumentation locates the seismic events, which are coloured by magnitude
- these indicate where rock breakage is taking place at the cave back
describe drift and fill mining method
a variant of cut and fill, expensive but maximises orebody recovery and mining precision, i.e., ore-waste separation
stope definition
generic term for an underground mined volume or working to extract ore, which is rock from which metal/mineral can be economically extracted
ore minerals definition
directly carry principal economic value e.g. chalcopyrite, chalcocite
gangue minerals definition
unwanted constituents e.g. silicates and carbonates in copper ore
deleterious minerals/elements definition
impact negatively on value, e.g. arsenic in sulphides
by-product minerals definition
carry minor saleable products e.g. molybdenum, gold, silver
run-of-mine (ROM) ore definition
ore flow from the mine
development definition
generic workings mined for other (non-ore) purposes e.g. access, transport, ventilation
drifts, drives, cross-cuts definition
drifts - horizontal workings parallel to orebody strike
drives - similar, larger, longer, generally for access
cross-cuts - similar, perpendicular to strike
fill definition
typically aggregates, sand and/or waste rock packed into exhausted stopes to fill void and provide a floor for stopes above
dilution definition
percentage of fill or waste rock mixed into ROM
ore recovery definition
percentage of orebody mined as ROM
volume variance relationship
the larger the sample volumes:
- the less random variation (i.e. variance)
- the more representative it is of the rock around it
- but more expensive to drill/process/analyse/assay
- its a trade-off
