MINE3634 CHAPTER1-5 FLASHCARDS

What is a mineral?

A naturally occurring material with characteristic chemical composition and crystal structure.

What is a rock?

A consolidated mixture of minerals such as quartz and feldspar in granite.

What qualifies a material as ore?

It contains valuable minerals that can be mined profitably.

What is gangue?

Unwanted mineral material associated with valuable minerals in ore.

What are native minerals? Give three examples.

Minerals occurring naturally in elemental form: gold and silver and copper.

Name three metallic minerals and their formulas.

Chalcopyrite = CuFeS₂ / Galena = PbS / Sphalerite = ZnS.

Name three nonmetallic minerals.

Quartz (SiO₂) / Halite (NaCl) / Sylvite (KCl).

What is isomorphism?

Atomic substitution without changing the basic crystal structure. Example: olivine.

What is polymorphism?

Same chemical composition with different crystal structures. Example: diamond and graphite.

Why is mineral processing necessary?

To increase ore grade and economic value while reducing waste entering costly processes.

What is mineral liberation?

Freeing valuable mineral grains from gangue through crushing and grinding.

What is a locked or composite particle?

A particle containing both valuable minerals and gangue.

What share of processing energy is attributed to size reduction?

Approximately 70% according to the Chapter 1 lecture estimate.

What properties are used in physical mineral separation?

Density / magnetism / electrical properties / hydrophobicity.

What does grade measure?

The percentage of valuable mineral or metal in a material stream.

What does recovery measure?

The percentage of feed valuable material collected in concentrate.

What does concentrate yield measure?

The percentage of total feed mass reporting to concentrate.

Why can higher recovery cause lower concentrate grade?

Recovering more particles may also collect gangue and mixed particles.

What is the copper content of pure chalcopyrite?

Approximately 34.6% Cu by mass even though it is 100% chalcopyrite mineral.

What is the total mass balance equation?

F = C + T where F is feed and C concentrate and T tailings.

What is the valuable-component mass balance?

Ff = Cc + Tt where lowercase symbols represent stream grades.

What is the fat-cat concentrate yield equation?

Yc = 100(f − t)/(c − t) = 100C/F.

How is metal recovery calculated using assays?

R = 100c(f − t)/[f(c − t)] = 100Cc/(Ff).

What is the separation efficiency equation?

SE = Ra − Rb or valuable-mineral recovery minus gangue recovery to concentrate.

What is a metallurgical balance sheet?

A table tracking stream masses and assays and contained metal and metal distribution.

How do you calculate contained metal value?

Ore mass × metal grade as a fraction × metal price.

What is Net Smelter Return (NSR)?

Metal payment minus smelting/refining and transportation charges.

What was the largest processing-cost category on slide 39?

Grinding at 47% of costs in the lecture's example concentrator.

What is an assay?

An analysis that determines a sample's chemical composition or grade.

Why do product purity and impurities affect value?

Customers require specifications. Impurities can cause penalties or reduce payment.

How do bulk and particle-by-particle analyses differ?

Bulk measures overall composition. Particle analysis reveals individual mineral associations.

What does XRF measure?

Elemental composition using characteristic secondary X-rays.

How does XRF work?

Primary X-rays excite atoms. Returning electrons emit element-characteristic X-rays.

What important limitation does XRF have?

Poor detection of low-atomic-number elements such as Li and C and N and O.

What sample-preparation step commonly precedes ICP?

Digestion of solid samples in acids.

How does ICP-OES/AES detect elements?

By measuring characteristic optical emission from excited atoms or ions.

Why is ICP-MS useful for trace-element analysis?

It uses mass spectrometry with excellent low detection limits.

What is the main purpose of XRD?

Identifying crystalline mineral phases and crystal structure.

What is Bragg's Law?

nλ = 2d sinθ relating wavelength and crystal-plane spacing and diffraction angle.

What four properties does coal TGA proximate analysis report?

Moisture / volatile matter / fixed carbon / ash.

What does a carbon and sulfur analyzer (CSA) measure?

Carbon and sulfur through oxygen-rich combustion and gas detection.

What is QEMSCAN used for?

Particle-by-particle mineralogy and mineral associations and liberation analysis.

Why is defining irregular particle size difficult?

Different size measurements can give different diameters for the same particle.

What is equivalent volume diameter?

Diameter of a sphere having the same volume as the particle.

What is Stokes diameter?

Diameter of a same-density sphere having the same terminal settling velocity.

What is sieve diameter?

The smallest square sieve opening a particle can pass without deforming.

What is particle size distribution (PSD)?

The distribution of material among different particle-size classes.

How is individual percentage retained calculated?

100 × mass retained on sieve / total sample mass.

How are cumulative retained and passing related?

Cumulative % passing = 100 − cumulative % retained.

What does a particle-size frequency plot show?

Individual percentage retained versus sieve size and dominant size fractions.

What does d50 represent?

Particle size below which 50% of material passes on the specified distribution basis.

What does d90 represent?

Particle size below which 90% of material passes.

What is the Gates–Gaudin–Schuhmann equation?

Y = 100(d/k)^m with Y as cumulative percent passing.

What does Y represent in the GGS equation?

Cumulative percent passing. GGS commonly describes fine mineral products.

What is the Rosin–Rammler equation?

Y = exp[−(d/k)^m] with Y as cumulative fraction retained.

What does Y represent in Rosin–Rammler?

Cumulative fraction retained between 0 and 1 rather than percent passing.

What do k and m represent in particle-size models?

k is the size modulus. m is the distribution modulus describing spread.

How does laser diffraction determine particle size?

It analyzes angles and intensities of light scattered by particles.

How do large and small particles differ in light scattering?

Large: narrow-angle scattering. Small: wider-angle scattering.

Why do large particles dominate volume-weighted PSDs?

Sphere volume scales with diameter cubed. Doubling diameter multiplies volume by 8.

What is comminution?

Particle size reduction by crushing and grinding to liberate valuable minerals.

What is the main role of crushing?

Initial coarse size reduction of mined material. Generally performed dry.

What is the main role of grinding?

Downstream fine size reduction for liberation. Usually performed wet.

What do F80 and P80 mean?

Sizes at which 80% of feed and 80% of product pass respectively.

What is the reduction ratio equation?

RR = feed size / product size. Commonly F80/P80 with consistent units.

How does a jaw crusher work?

A moving jaw compresses rock against a fixed jaw.

How does a gyratory crusher operate?

A gyrating inner mantle crushes rock against a stationary outer shell.

What crushing stage commonly uses cone crushers?

Secondary or tertiary crushing using a mantle and concave bowl.

How does a roll crusher reduce size?

It squeezes material between rolls. Roll spacing influences product size.

How does an impact crusher break rock?

High-speed rotor impacts and collisions with crushing surfaces.

What does choke feeding mean?

Keeping the crushing chamber continuously full of material.

How do rod mills and ball mills differ?

Rod mills use rods for coarser grinding. Ball mills use balls for finer grinding.

What is the difference between AG and SAG mills?

AG uses ore as grinding media. SAG uses ore plus added steel balls.

What is the ball-mill critical-speed equation?

Nc = 76.6/√(Dm − Db) rpm with diameters in feet.

What are cascading and cataracting and centrifuging?

Cascading: slow / Cataracting: effective impact / Centrifuging: media pinned to shell.

What distinguishes open and closed grinding circuits?

Open: product exits directly. Closed: classifier returns oversize for regrinding.

How is circulating load calculated?

CL = 100 × recycle solids flow / fresh-feed solids flow.

What is gravity concentration?

Separating minerals by differences in density and settling behavior in a fluid.

What is the concentration criterion equation?

CC = (ρh − ρf)/(ρl − ρf) using heavy and fluid and light densities.

What does CC greater than 2.5 indicate?

Relatively easy gravity separation under the lecture's classification.

What is the concentration criterion for gold vs. quartz in water?

Approximately 11.1 indicating very favorable gravity separation.

Name the three gravity-separator families.

Vertical-current / flowing-film / dense-medium separators.

What is the purpose of jigging?

Stratifying particles by density so heavy particles settle below lighter particles.

What happens during jig pulsion and suction?

Pulsion expands the bed upward. Suction promotes settling and consolidation.

What is differential initial acceleration in jigging?

Dense particles accelerate faster at the start of settling before drag becomes significant.

What equation describes initial particle acceleration in jigging?

a = g(1 − ρf/ρs). Initially independent of particle size in the lecture model.

What is hindered settling?

Particles settle in a concentrated bed where neighboring particles impede their motion.

What is consolidation trickling?

Small dense grains fall through gaps between larger particles as the bed compacts.

What are two major advantages of jigs?

They handle a broad feed-size range and can achieve very high throughput.

What two feed conditions make jigging less effective?

Too many near-density particles or excessive fine slimes.

What does the jigging ratio compare?

Particle sizes of different-density materials traveling equivalent settling distances.

What is flowing-film separation?

Density separation in a thin fluid layer flowing over an inclined surface.

What are primary and secondary flows in spirals?

Primary flow moves down the trough. Secondary flow circulates across its cross-section.

What is the advantage of double-start spirals?

Two spiral trough starts on one column. Approximately double the capacity.

Why is enhanced gravity useful?

Centrifugal forces around 50–300g improve separation of fine particles.

What is the principle of dense-medium separation?

Intermediate-density medium causes light material to float and heavy material to sink.

What density relationship is needed for DMS?

ρfloat < ρmedium < ρsink.

Which two dense solids are commonly used in DMS media?

Magnetite (SG ≈ 5) and ferrosilicon (SG ≈ 6.7–6.9).

How do the inner and outer flows move in a dense-medium cyclone?

Outer spiral flows downward. Inner spiral flows upward.

What happens to dense medium after DMS separation?

Drain and wash screens remove medium. Magnetic separation recovers it for recycle.