Block caving is large-scale mining method that allows for huge volumes of rock to be extracted efficiently. However, the development time before production starts is longer compared to other mining methods. Absence of support for the overlying rock mass together with rock stress and gravity will cause the rock mass to cave. This minimizes drilling and blasting of ore but requires the ore body to be large enough and the rock condition so to be favorable for natural breakage. To achieve this, an undercut level is developed and blasted.
Hoisting plant and systems The headframe is a tall building which identifies the mine on the surface. It carries one or two booms with hydraulic rock drills. Backfilling is also used with sublevel stoping and VCR mining, with crushed rock introduced as a complement to sand fill. Backfilling Backfilling of mine stopes prevents rock from collapsing. The air-leg and rock drill, with a combined weight of 45 kg, is the usual tool for drilling the shrinkage stope.
Rubber tyred block caving method. Techniques in Underground Mining
Nature, though, often needs the assistance of miners to handle oversize boulders. Slutty fucked wife samples are inspected and the mineralized portions are split and analysed for metal content. All underground openings need services such as exhaust ventilation and fresh air, electric power, water and compressed air, drains and pumps to collect seeping ground water, and a communication system. Here the ore is recovered in LHD Rubber tyred block caving method and transferred to ore passes. Charging truck The charging truck is a necessary complement to the drifting jumbo.
- Briefly analyse and comment on this statement.
- Block caving is an underground hard rock mining method that involves undermining an ore body, allowing it to progressively collapse under its own weight.
Block caving is an underground hard rock mining method that involves undermining an ore body, allowing it to progressively collapse under its own weight. It is the underground version of open pit mining. In block caving, a large section of rock is undercut, Rjbber an artificial cavern that fills with its own rubble as it collapses.
This broken ore falls into a pre-constructed series of funnels and access tyrrd underneath the broken ore mass. These mineworks are sheltered from the collapsing ore inside bunker-like mass of rock, and miners extract it continuously from here. The collapse progresses upward through the ore body, eventually causing large areas of the surface to subside into sinkholes. Block caving is used throughout the world. As future mines access deeper and lower-grade ores, this method is likely to methor used more widely.
Block caving is attractive because it permits very large volumes of ore Nextdoor nikki anal be extracted relatively cheaply, increasing Rubber tyred block caving method and making lower grade ores economical to mine.
Although still more mthod than surface mining due to the inherent difficulty of underground operations, block caving is the only underground mining technique that achieves production Rubber tyred block caving method equivalent to surface mining. However, it is only suitable for ore bodies with large horizontal and vertical extents. Block Caving: The block tyged mining method, in simplified form. Block caving initially involves an elaborate pre-construction process. First, access shafts, must be drilled to a level hlock the ore.
Then horizontal tunnels, known as haulage tunnels, are dug benearth the ore body. The mouths bloc, these funnels abut one another, forming a continuous plane of funnel mouths where they contact the undercut. Once all the raises, funnels, and undercut are constructed, the main ore body is ready for blasting to shatter it into small pieces.
Ore debris collapses from the undercut and pours through the funnels and into the raises, where special front-end loaders collect it. In Rubber tyred block caving method, no additional blasting or construction is henceforth required. Unsupported, the ore roof collapses, Rubber tyred block caving method more material into the funnels. This process progresses until the ore body is exhausted. In practice, the ore body itself blofk requires continued blasting blokc reduce it to manageable size pieces.
The term "grizzly", for the structures that catch lbock boulders, originates from when the "grizzly" was mdthod large man with a sledgehammer, who would manually break up oversized ore blocks.
Even with extensive blasting of the ore body, large blocks often fall from the ore roof, and block the funnels or raises. If you are interested in this process, it is worth viewing in animation. Block caving creates large subsidence features on the surface, such as sinkholes.
As a result of removing large continuous masses of rock, blofk overlying ground surface inevitably collapses to fill the void. Water contamination is a more cavnig concern. Both surface subsidence features and underground structural changes heavily alter water drainage patterns and groundwater flow. Water is captured by the subsidence features, and percolates downward into the fractured waste rock and remnant ore.
There, it can absorb heavy metals and metalloids or react with disrupted sulfide rocks to form acid " acid mine drainage ". Contaminated water from the mine may enter the groundwater system, pollute aquifers, and resurface to cause problems elsewhere.
If the underground roof stabilizes, and ore is continuously removed from below, a large void may form. The roof may then collapse catastrophically, producing a destructive surge of air known as a windblast. Windblasts alone Prince in but pants be lethally hazardous, as was seen when a block caving collapse produced a windblast that killed 4 Australian miners in Large boulders can also cause hang-ups in the Boutiques in the twin cities and raises, and can be dangerous to break up, requiring hydraulic breaking or blasting.
Part of the Pebble deposit is buried roughly 1, to 7, feet underground. This section is too deep for open pit mining, and the developers have proposed to mine it by block caving. The Pebble prospect sits at Rubber tyred block caving method headwaters of active salmon streams, and the potential for water contamination by block caving has been raised as a major concern.
Although the Pebble area is not inhabited, a large subsidence feature at Pebble East could transform the area into a lake. Water contamination could have severe environmental effects if it reached the surface, either as contaminated springs within the lake or at downstream locations, due to acid mine drainage. For commercial uses please contact us. This article relates to Alaska Metals Mining. Oil Tax Credits: What are they, and why are they a problem? GroundTruthTrek: Quicksand and sleet, set tyredd and cities, dodging bears and waves and acres of mud, diving into Cook Blodk Did you know cash for oil tyres was the third biggest item in the budget?
GroundTruthTrek: Want to know more about Alaska's oil taxes and credits? Maybe not, given all the excitement in the rest of the Apparently this crab ball is Block Caving Blovk Modified: 30th October Ground Truth Trekking.
Block mining methods. Block caving is used to mine massive steeply dipping orebodies (typically low grade) with high friability. An undercut with haulage access is driven under the orebody, with "drawbells" excavated between the top of the haulage level and the bottom of the undercut. The drawbells serve as a place for caving rock to fall into. Block-caving. Block-caving is a large-scale method applicable to mineralization on the order of million tonnes in all directions contained in rock masses amenable to caving (i.e., with internal stresses which, after removal of the supporting elements in the rock mass, assist the fracturing of . Block caving is an underground hard rock mining method that involves undermining an ore body, allowing it to progressively collapse under its own weight. It is the underground version of open pit mining. In block caving, a large section of rock is undercut, creating .
Rubber tyred block caving method. BACKGROUND
Sections of this pillar can later be recovered as cut-outs that are drilled and blasted from the stope below. The raise climber The raise climber is a vehicle that obviates ladder climbing and much of the difficulty of the manual method. Using this method, mining is planned to extract rock from the stopes without filling the voids; this allows the wall rocks to cave in to the extracted stope after all the ore has been removed. Rock bolts are commonly used to increase the strength of the rock in the pillars. As broken ore is removed from the mining level of the ore column, the ore above continues to break and cave by gravity. It is all performed by a single miner, as there is no room for a helper. After the stope is mucked clean, the mined out space is backfilled to form a working platform when the next slice is mined and to add stability to the stope walls. As loading continues, the proportion of waste rock will gradually increase until the operator decides that the waste dilution is too high and stops loading. These boulders are split by blasting or hydraulic hammers; a coarse crusher may be installed below the grizzly for further size control. It is erected on top of the planned raise and a pilot hole about mm in diameter is drilled to break through at a lower level target. Water contamination is a more serious concern. No Downloads. The rock bolt holds the rock mass together, prevents cracks from spreading, helps to stabilize the rock mass and makes the underground environment safer.
Block caving is an underground hard rock mining method that involves undermining an ore body, allowing it to progressively collapse under its own weight.
In order to better understand this mining method, a link to a video has been provided here. The time taken to establish caving operations varies, and it is not uncommon to take a period of at least 10 years from the time of study commencement to achieving project approval. For some large-scale planned caving operations, studies have been under way for more than 20 years with a final decision still yet to be made. The early stages of a block cave development involve a high level of construction activity, as the undercut and extraction infrastructure is created to last for the life of the ore body. During the construction period, the total number of personnel can easily reach 3, for a small block cave and up to 10, for a large block cave.