9-coal mining complete

7/28/2019 9-Coal Mining Complete

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PART X

IRONMAKING COURSE

March 12th, Belo Horizonte, Brazil

Coal Mining


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Coal Mining

Ground

DrillingExplosion

CoalCoal LayerLayer


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Coal Mining

Work of coal extracting from its natural environment, processing andtransportation to the place that it will be used.

Disassembly of the coal layer (drilling and / or detonation with explosives),

charging, transporting and crushing to a suitable size for further processing.


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Coal Mining

Stages of the coal industry

1. Exploratory

Geological ResearchGeophysical ResearchDrilling Research

2. Viability Studying

3. ExplorationMining DevelopmentMining OperationCoal processing

4. Transportation

5. Utilization


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Coal Mining

Activities before coal mining

Deposit

GeologyMineralogy

Mining methodsMineral processing

EconomyEnvironment

Planning

Mininh methods seletioninstallation needs

Project and engineering

OPENING AND

DEVELOPMENT

Opening of the pit andtunnels

Stripping

Surfaces and undergroundsconstructions

Coal localization and

avaliation

Local Geology

GeophysicsGeochemistry

DrillingSampling

Reserves evaluation

Drill ing (mash)Pit or tunnel drillingEvaluation

Mining


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Coal Mining

The first stage for the implantation of a mining unit is the establishment of aresearch program, drilling teams, using simultaneously several drilling machines,take the probe evidency.

Probe evidence are samples of 50 mm in diameter for definition of reserves /characterization of coal or 200 mm in diameter, in sufficient quantities for varioustests, including those of washability.

Tests can get information on coal quality on the geological layer characteristics,

providing a perfect project of the mine, of the preparation plant and thesubsequent use of coal.


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Coal Mining

E

X

PL

O

RA

T

O

R

Y

Probe

evidency

Probe or drill ingtower

Drilling columnTubes

First tube: drill


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Coal Mining

Organic Matter

Inorganic

Moisture

Organic Matter

Inorganic

Moisture

Float-Sink

Test

Complete characterization

Mining

BeneficiationApl icat ion

Complete characterization


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Coal Mining

Washability curve

It is made by the determination of the properties (ash, volatile matter and sulfur)of the fractions that sink to a certain density of the dense liquid and float intoanother density a bit higher. It also determines the percentage by weight of eachof these fractions.

Os valores acumulados so calculados, tabelando-se os rendimentos, matriavoltil, cinza e enxofre para os carves flutuados em diversas densidades. O

carvo metalrgico considerado como o flutuado em meio denso a vriasdensidades.

A planta de preparao projetada para remover a poro no-combustvel docarvo a um custo operacional mnimo e um rendimento timo.


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Coal Mining

Types of Coal Mining

UndergroundUnderground

Ground

DrillingExplosion

CoalCoal LayerLayer

Open Pit


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Coal Mining

Stages of coal mining

Mining

Disassembly

Charging Transport

Costs control

Environment

GeologySampling

ResearchDigging stability

Project and engineeringSuply services

EnergyMaintenanceOccupational health andsecurityVentilationWater controlLand recovering

ROM


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Coal Mining

Steps to coal mining:

Depth of coal layer.

Thickness of coal layer.

Quantity and type of sediments overlapped.

Quantity of water encountered.

Presence and quantity of gas in the layer.

Other geological conditions, roof stability, existence of igneous inclusions, dipangle of the layer, existence of flaws.


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Coal Mining

Open pit


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Coal Mining

Open Pit


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Coal Mining

Open Pit


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Coal Mining

Open Pit


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Coal Mining

Open Pit


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Coal Mining

Underground Mining


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Coal Mining

Underground Mining


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Coal Mining

Underground Mining


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Coal Mining

Underground Mining


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Coal Mining

Underground Mining


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Coal Mining

Underground Mining


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Coal Mining

Underground Mining


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Coal Mining

Underground mining


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Coal Mining

Underground Mining


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Coal Mining

Underground Mining

ChambersChambers andand pillarspillars


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Coal Mining

Underground mining Longwall


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Coal Mining

Underground Mining Longwall


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Coal Mining

Underground Mining Longwall


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Coal Mining

Coal Processing

Processing

ROM conversion toconsumable

products

ROM

Comsumption products

ClassificationProcessing

PesquisaDigging stability

Project and engineeringSuply services

EnergyMaintenanceOccupational health andsecurityVentilationWater controlLand recovery


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Coal Mining

Coal processing

RunRun--ofof--MineMine

vvVarietyVariety ofofsizessizes

vvHighHigh contentcontent ofof

impuritiesimpurities

ProcessProcess

vvCrushingCrushing

vvClassificationClassificationvvWashingWashing

vvDryingDrying

WashedWashed coalcoal

vvSmall rangeSmall range ofofsizessizes

vvLowLow contentcontent ofof impuritiesimpurities

The processing method use the density to remove impurities.

Magnetite is added to water to create an ambient in which multiple density levels arecreated.

Different qualities of coal are produced


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Coal Mining

Coal beneficiation

Tailing bunker

Clean coal Clean coal Clean coal

Thermal Dryer

Clean coal filter

Dewatering screen

Centrifuging

Dewatering screen

Froth Flotation

Tailing

CycloneTailing

Bathing with densefluid

Tailing

Fine coal Medium coal Thick coal

Run-of-Mine

Crusher

Tailing Thickner

Charging


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Coal Mining

Coal beneficiation

Pre-scrubber

Run-of-Mine55 to 60% of ash

1000 t

243 t

17 t

12 t 740 t

60 t 170 t

Scrubber

752 t

Fines (18% ash)Metalurgical Coal

(18% ash)Seam Coal

(30 to 40% ash)Tailings

(70 to 75% of ash)


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Coal Mining

Coal marketing

Consumption products

MARKETING

Coal forcokemaking

and oters uses.

Definition of coal typesStandards and specificationsTransport to the costumers

Materials science and technologyProperties and products uses.Ways of sales.

C l P i f Th C k O Pl


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Coal Preparation for The Coke Oven Plant

C l P ti S t


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Coal Preparation System

Storage yards

Marit ime Terminal

Railway transportation

Conveyors belt system

Dumper wagon

Coal sampler

Magnetic separator

Magnetic separator

Coal bunker

Scales system

Mechanical Mixer

Coal Blend BunkerBlending sampler Coke oven battery

Coal sampling

Crushing system

C D


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Car Dumper

CarCardumperdumperwithwith waterwatersprayssprays

AutomaticAutomatic weighingweighing andand emptyingemptying

Storage in Yards of Steel Industry


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Dead storage (to prevent transportation problems and keep a steady flow) andalive storage (supplies directly the consumer or the means of transport): the coal

is removed from the dead and transferred to the alive.

Silo between regular consumption of coke oven battery and irregular receivingof ships.

Open storage (outdoor):is used for large capacity, due to its lower cost in

relation to the closed storage.



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Thick green belt around the yards.

Covered conveyor belts.

Stacking and removal of coal (distribution-reclaiming).

Individual Stacks by type of coal.

Increase the homogeneity of the coal.

Limiting the storage time to prevent more severe oxidation of coal.

Distribution by Stacker


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Distribution by Stacker

Distribution by Stacker-Reclaimer


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Maximum height of fall during stacking.Maximum height of fall during stacking.

Maximum height of stacks.Maximum height of stacks.

Stacks located appropriately in relation to the wind direction.Stacks located appropriately in relation to the wind direction.

Water spray systems on conveyor belts before stacking.Water spray systems on conveyor belts before stacking.

Automated system of spraying water in the stacks.Automated system of spraying water in the stacks.

Tailing ponds for contention of the material carried by the wateTailing ponds for contention of the material carried by the waters.rs.

Coal Distribution System by Stacker-Reclaimer


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Coal Distribution System by Stacker Reclaimer

The system consists of a feeder conveyor belt, a conveyor belt of reversecycle and a bucket wheel.

The coal is carried by the feed conveyor to an intermediate transfer point,

where it is transferred to a reverse conveyor belt, which takes the coal tothe point of storage.

Coal Distribution in Yards


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Coal Distribution in Yards

It should prevent the occurrence of segregation that makes the particles

of larger diameter be located in the outer and bottom stack zones and the

smaller diameter in the inner and higher stack zones. This arrangement

facilitates the movement of air currents through the larger particles, which

carry oxygen to the border region with smaller particles, due it has higher

specific surface are susceptible to oxidation, may generate hot points. It canlead to located deterioration of coal.

Segregation in Coal Stacks


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Segregation in Coal Stacks

Stacking Methods


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g

WWindrowindrow ,, chevronchevron ee conecone--shellshell

Windrow Method Parallel Stacks


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It is (with the stacker) a series of parallel stacks along the tyard, covering theentire area of the stack soil.

When the first series of steps is completed a second row of stacks is constructedby filling the gaps in the first serie of stacks.

The process continues until the entire stack is built (it can be flat-topped or not).

The advantage of this type of stack is that it avoids the segregation (thearrangement of thicker material for each step is restricted by the triangular

section)

The thick material is distributed consistently throughout the stack.

The method can be applied only if the scope of the stacker reaches the extremity

of the yard.

Chevron Method


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Consists in crossing from one side to another throughout the length of the courtwith the stacker arranged to feed the center of stack.

A small stack of triangular section is deposited along the length of the court in thefirst step of the stacker.

In the second step in the opposite direction a second chevron of coal will beplaced on the top of the first.

As the number of steps increases the stack increases in height and thickness of

chevrons reduces progressively (the same amount of material trying to cover aperimeter of increased cross section).

If there is thick coal the main disadvantage of these methods is that there will be

segregation and larger particles tend to be deposited in the lower and outsideparts of the stackl.

Depending on the method of reclaiming used this method may not give the resultsof homogeneity required.


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Evaluation in Yards Emissions


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Method for measuring emissions with wind tunnel (for stacks).Method for measuring the exposure profile (transfer points).Method of measurements of wind barriers (green belt).Quantification of settable dust (point counting technique on body-of-evidence produced from samples collected in different parts of the plant andin locations close to it).

Dreinage Water in Yards


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Drainage water from coal stacks may have three undesirable aspectsregarding the viewpoint of use:

high acidity, resulting from oxidation of pyrite (neutralization is madeby adding lime or limestone);

contain particulate matter in suspension by mechanical drag made

by percolation water (this material may have dimensions such that itbehaves as colloid, dispersing in the liquid mass with slowsedimentation rate), and

contain heavy metals (such as Fe, Pb, Zn, Cd and Hg) dissolved inwater, resulting from the leaching action of acidic water (these metalscan be precipitated at higher pH and removed with particulate materialin devices called classifiers or thickeners).

Unstacking: Reclaimer or Jib-Loader


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Unstacking of Coal in Yards


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With Reclaimer: the unstacking of coal is made by the bucket wheels whichtransfer the coal to reverse conveyor belt (now goes in the opposite direction)and will discharge it in the feed conveyor, which takes the coal for further

processing.

Types of Unstacking


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BenchBench cutcut, module, module cutcut ee harrowharrow cutcut..

Oxidation During Coal Storage


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Coal is a pyrophoric substance "spontaneous combustion" .

WIND

If the O2 penetrates the stack, itoxidizes.

Increase oftemperature.

If the heat generated is not wellremoved, it eventually ignites.

+ O2 H2O CO2+ + HEATC

H

Oxidation Consequences


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Reducing of rheological propertiesDecrease of the mechanical strength of coke

Control problems with charge density.

Variations in the coke production.Overheated charges.

Carbon deposit

Ovens deterioration

Increase of coke reactivity.

Decrease of coking rate.

Fines generation and difficult of handling.

Spontaneous combustion.

Sponge effect when adding oil.

Monitoring Oxidation Level


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Systematic monitoring of coal received quality (rheological properties)Observation and petrographic analysis

Extraction method with probe.

Steps to Prevent Oxidation


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Stacks compressionMonitoring and eliminating hot pointsMinimize pressure of the winds

9-coal mining complete

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