Mine Dust and Mine Gases Their Sources and ControlPresented By:Ali Bux Wassan (12MN65)Under kind supervision of:Sir, Saeed Ahmed Memon Sb.

Mine Dust-its sources and control

Introduction:Throughout the mining and processing of minerals, the mined ore undergoes a number of crushing, grinding, cleaning, drying, and product sizing operations as it is processed into a marketable commodity.

These operations are highly mechanized, and both individually and collectively these processes can generate large amounts of dust. If control technologies are inadequate, hazardous levels of respirable dust may be liberated into the work environment, potentially exposing workers.Accordingly, federal regulations are in place to limit the respirable dust exposure of mine workers.

Engineering controls are implemented in mining operations in an effort to reduce dust generation and limit worker exposure.

Dust Control In Any Mine Is A Large Complex Problem Dust can cause health related issues whether it is a short acute related health problem or a long term systemic problem like silicosis. Prevention of dust is everyones problem. We all breath the same air, if we dont take care of it. In other words: It can kill you.

Why Can Dust Get So Bad Here?

Fact: Major dust compliance problems in hard rock mines is caused by silica (quartz) in the rock. Mines high in silica content rock, 8% or more, are far more likely to have dust problems than those where there is less silica.Fact: On average the rock in this mine is 40% silica content. Depending where you mine it can go higher.Fact: Exposure to silica dust can cause silicosis.

Major Source of Dust GenerationBlastingMucking & HaulageDrilling & BoltingOre passes CrushersConveyors SystemsBackfill ProcessRoad HeadersShotcretingFresh Intake Mine Dust

Control Measures for Correction & Reduction in DustWater sprays & Spray BarsVentilationControl of drill dustControl of conveyor dustControl of ore pass dustControl of mucking & haulage dustControl of blasting dustControl of road-header dustControl of fresh air intake dust

Control Measures

Drill Dust ControlGood Dust ControlRequires Good Regular & Consistent MaintenanceFactors that can lead to high dust levels on drills:Lack of Proper MaintenanceFailure to use waterInadequate quantities of waterPlugged water holes in drill steels Dull drill bitsDry collaring.Poor Maintenance on dust collector systems

Crushers & Rock BreakersWater Sprays SystemsDust Collector SystemsVentilation SystemsAll require regular maintenance & attention. Disabling dust control systems are a bad practice that can cause long term health threats.

Conveyor Belt Dust Control

Possible Solutions to Conveyor System Dust

Solutions to Conveyor Transfer Box Dust May Require Installing & Properly Maintaining Dust Collector Systems Moving Rock Moves Air.

Maintenance of Water Spray & Sprinkler Systems

Solving Ore Pass DustA critical step in dust control is to prevent its escape & dispersal.Confinement can be accomplished by systems of stoppings & air tight doors, curtains, spray bars, or isolations of passes away from travelways.Dust can be reduce by wetting before delivery & adding water at the tipping site by spraying rock as it falls into passes.

Mucking & Haulage Dust ControlLarge Strides can be made to improve dust during this cycle.Improvement to water trucks sprinklers.Installation of mine wide sprinkler systems.Dust surfactants testing & implementations.Wetting down entire muck area prior to removal of material.

Blasting Dust ControlThoroughly wetting down area surrounding the blast (Back, Ribs & Seal) before a blast will help settle dust from previous operations from becoming airborne.

Blasting Dust ControlUniform rock moisture content of only 1% greatly reduces dust compared to dry rock both before & after a blast.

Shotcreting Dust ControlNote: Predampening & washing down of rock surfaces in shotcreting zone will greatly improve adhesion of product & eliminates a lot of dust that can be liberated during pneumatic application of product.When dry systems are utilized predampening of product can reduce dust.Also spray bars in close proximity can knock down goodly amounts of generated dust.

Road Header Dust ControlDust Control for machines like roadheaders usually depend on some degree of dust cloud confinement.

Road Header Dust Control Managed Through Ventilation & Water Sprays

Fresh Air Intake DustDust is liberated from other sources (i.e. process facilities, haul roads, backfill stockpiles.Possible solutions: Surface application of dust surfactants around fresh air intakes.Increased water trucks scheduling.Better dust control at surface crusher facilities.

Respiratory ProtectionUltimately it is the objective of the safety department to do away with mandatory respiratory protection for all underground personnel. This will only be possible by diligent efforts of all personnel underground. There are definitely in roads that need to be made. Some of it is behavioral. Some of it is improvement in conditions that create dust releases. It will require everyones help & active participations to solve.

Mine Gases-Their sources and control

Sources of GasesIn a mine oxygen is abstracted from the air chiefly: (a) by the gradual oxidation of coal and other carbonaceous minerals and to a smaller degree. (b) by the breathing of men and animals, and (c) by the burning of lights carbon dioxide is added by these same three processes and(d) in some mines it is given off by the coal and adjacent strata.

Other noxious gases intrude themselves into the mine air by the variety of means chief among these is the evolution of methane (the chief constituent of firedamp) from the coal and associated strata, resulting in the displacement of a corresponding proportion of air.

And it contains conditions to the danger of an explosion of some what less importance (because on a smaller scale). production of nitrous fumes from explosives, whilst under abnormal conditions e.g. when spontaneous combustion takes place or in the after damp of an explosion the two deadly poisonous gases, carbon monoxide and hydrogen sulphide (sulphurated hydrogen) must be reckoned with.

Mine Gases ControlPreventionRemovalDilutionAbsorptionSuppressionUse PPE