Question

Write a note on shaft mining.

Answer 1

Shaft mining or shaft sinking is excavating a vertical or near-vertical tunnel from the top down, where there is initially no access to the bottom.

Shallow shafts, typically sunk for civil engineering projects differ greatly in execution method from deep shafts, typically sunk for mining projects. When the top of the excavation is the ground surface, it is referred to as a shaft; when the top of the excavation is underground, it is called a winze or a sub-shaft. Small shafts may be excavated upwards from within an existing mine as long as there is access at the bottom, in which case they are called Raises. A shaft may be either vertical or inclined (between 45 and 90 degrees to the horizontal), although most modern mine shafts are vertical. If access exists at the bottom of the proposed shaft and ground conditions allow then raise boring may be used to excavate the shaft from the bottom up, such shafts are called borehole shafts. Shaft sinking is one of the most difficult of all development methods: restricted space, gravity, groundwater and specialized procedures make the task quite formidable.

Historically mine shaft sinking has been among the most dangerous of all the mining occupations and the preserve of mining contractors called sinkers.Today shaft sinking contractors are concentrated in Canada, Germany andSouth Africa.

Answer 2

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♻ӇЄƦЄ ƖƧ ƳƠƲƦ ƛƝƧƜЄƦ♻
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sʜᴀғᴛ ᴍɪɴɪɴɢ ᴏʀ sʜᴀғᴛ sɪɴᴋɪɴɢ ɪs ᴇxᴄᴀᴠᴀᴛɪɴɢ ᴀ ᴠᴇʀᴛɪᴄᴀʟ ᴏʀ ɴᴇᴀʀ-ᴠᴇʀᴛɪᴄᴀʟ ᴛᴜɴɴᴇʟ ғʀᴏᴍ ᴛʜᴇ ᴛᴏᴘ ᴅᴏᴡɴ, ᴡʜᴇʀᴇ ᴛʜᴇʀᴇ ɪs ɪɴɪᴛɪᴀʟʟʏ ɴᴏ ᴀᴄᴄᴇss ᴛᴏ ᴛʜᴇ ʙᴏᴛᴛᴏᴍ.

sʜᴀғᴛ ᴍɪɴɪɴɢ ɪs ᴀ ғᴏʀᴍ ᴏғ ᴜɴᴅᴇʀɢʀᴏᴜɴᴅ ᴍɪɴɪɴɢ ᴜsɪɴɢ sʜᴀғᴛs ᴅʀɪᴠᴇɴ ᴠᴇʀᴛɪᴄᴀʟʟʏ ғʀᴏᴍ ᴛʜᴇ ᴛᴏᴘ ᴅᴏᴡɴ ɪɴᴛᴏ ᴛʜᴇ ᴇᴀʀᴛʜ ᴛᴏ ᴀᴄᴄᴇss ᴏʀᴇ ᴏʀ ᴍɪɴᴇʀᴀʟs. sʜᴀғᴛ ᴍɪɴɪɴɢ, ᴀʟsᴏ ᴛᴇʀᴍᴇᴅ sʜᴀғᴛ sɪɴᴋɪɴɢ, ɪs ᴘᴀʀᴛɪᴄᴜʟᴀʀʟʏ ɪᴅᴇᴀʟ ғᴏʀ ᴄᴏɴᴄᴇɴᴛʀᴀᴛᴇᴅ ᴍɪɴᴇʀᴀʟ ᴅᴇᴘᴏsɪᴛs, sᴜᴄʜ ᴀs ɪʀᴏɴ ᴏʀ ᴄᴏᴀʟ, ᴛʜᴀᴛ ᴀʀᴇ ᴅᴇᴇᴘʟʏ ɪᴍʙᴇᴅᴅᴇᴅ ᴜɴᴅᴇʀɢʀᴏᴜɴᴅ.

ᴛʜᴇ ᴇɴᴠɪʀᴏɴᴍᴇɴᴛᴀʟ ɪᴍᴘᴀᴄᴛ ᴏғ ᴍɪɴɪɴɢɪɴᴄʟᴜᴅᴇs ᴇʀᴏsɪᴏɴ, ғᴏʀᴍᴀᴛɪᴏɴ ᴏғ sɪɴᴋʜᴏʟᴇs, ʟᴏss ᴏғ ʙɪᴏᴅɪᴠᴇʀsɪᴛʏ, ᴀɴᴅ ᴄᴏɴᴛᴀᴍɪɴᴀᴛɪᴏɴ ᴏғ sᴏɪʟ, ɢʀᴏᴜɴᴅᴡᴀᴛᴇʀ, ᴀɴᴅ sᴜʀғᴀᴄᴇ ᴡᴀᴛᴇʀ ʙʏ ᴄʜᴇᴍɪᴄᴀʟs.