Directional Terms
Breast - Advancing in a near - horizontal direction , also the working face of an opening
Inby - Towards the working face , away from the mine entrance
Outby - Away from the working face , towards the entrance
Overhand - Advancing in an upward direction
Underhand - Advancing in downward direction
Excavation Terms
Adit - main horizontal or near - horizontal underground opening , with single access to the surface
Bell - funnel shaped excavation formed at the top of a raise to move bulk material by gravity from a stop to a drawpoint
Bleeder - Exhaust ventilation lateral
Sunday, December 29, 2013
Underground Mine Development
Terms
Deposit and Spatial Terms
Back - roof , top , or overlying surface of an underground excavationBottom - floor or underlying surface of an underground excavation
Capping - waste material overlying the mineral deposit
Country rock - waste material adjacent to a mineral deposit
Crown pillar - portion of the deposit overlying an excavation and left in place as a pillar
Dip - angle of inclination of a deposit , measure from the horizontal, also pitch or attitude
Floor - Bottom or Underlying surface of an underground excavation
Footwall - wall rock under the deposit
Gob - Broken , caved , and mined out portion of the deposit
Hanging wall - wall rock above the deposit
Pillar - unmined portion of the deposit , providing support to the roof or hanging wall
Rib - Side wall of an excavation , also rib pillar
Roof - back , top , or overlying surface of an excavation
Sill pillar - portion of the deposit underlying an excavation and left in place as pillar
Strike - Horizontal bearing of a tabular deposit as its surface intersection
Wall rock - Country rock boundary adjacent to the deposite
Tuesday, December 3, 2013
Gemmology
Essential qualities of a gem material
1. Beauty
o
Colour
o
Clarity
2 . Rarity
Stones with special optical effects
Chatoyancy - Cat's eye
Asterism - Star sapphire
Play of colour - Opal
Adulresecence - Moonstone
Labradorecence - Labradorite
3. Durability/ Hardness
Classification of gem materials
- Minerals - inorganic origin
- organic gem materials
- Man made products
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