Is an activity best done in a simple (manual) or mechanical, including excavation, loosing, loading and transportation of minerals. Several stages of mining activity in general is:
1. Clearing (clearing)
2. Paring the ground cover (stripping)
3. Excavation extractive (mining)
4. Loading (loading)
5. Transportation (hauling)
6. Shedding (waste dump)
The factors in the selection of mining systems, namely:
1. Spatial nature of ore deposits
a. Size (dimensions: high or particularly thick)
b. Form (tabular, ventricular, massive, irregular)
c. Position (italics, horizontal or vertical)
d. Depth (average value, stripping ratio)
2. Geological and hydrological conditions
a. Mineralogy and Petrology (sulfide or oxide)
b. Chemical composition (the main byproduct, mineral by product)
c. Sedimentary structures (folds, faults, intrusions, discontinuity)
d. Weak field (thick, fracture, cleavage in the mineral, cleats in the coal)
e. Uniformity, alteration, erosion
f. Ground water and hydrology
3. Nature geo mechanic
a. Elastic properties (strength, elastic modulus, poison Value)
b. Behavioral plasticity or visco elastics (flow, creep)
c. State voltage (initial stress, induction)
d. Consolidation, compacting and competent
e. Physical properties of the other (specific contents, voids, porosity, permeability, moisture-free, humid congenital)
4. Economic Consideration
a. Backup (tonnage and levels)
b. Production
c. Mine life
d. Productivity
e. Comparison of the cost of mining for a suitable mining method
5. Technological factors
a. Obtaining mining
b. Dilution (the number of waste generated by ore)
c. Flexibility method to change the conditions
d. Selectivity methods for ore and waste
e. Concentration / distribution of work
Basis in the selection of mining methods are:
1. Stripping Ratio (SR)
That is how much waste (waste soil either O / B and rock side) that must be disposed / removed to obtain 1 ton of ore deposits to the ultimate pit limit.
Number of Waste (m3/ton)
SR = -------------------------------------
Number of Ore (m3/ton)
SR> 1 = The cost of stripping smaller (surface)
SR> 1 = higher stripping costs (undeground)
SR = 1 = Can surface / underground
2. Break Even Stripping Ratio (BESR)
Is the ratio between gross profits at the cost of disposal of O / B
Ore extraction cost
BESR = ---------------------------------------
Cost paring OB
To select the system of mining used the term BESR-1 for the overall open pit stripping ratio.
BESR-1> 1 = surface
BESR-1 <1 = underground
BESR = 2 = Can surface / underground
Then after a specified surface selected, then in order to develop the mining plan each stage of economic terms used stripping ratio (BESR-2).
Recovable value / ton of ore - Production cost / ton of ore
BESR-2 = ------------------------------------------------------------
Stripping cost / ton ore
BESR-2 to determine the maximum number of tons of waste removed to obtain 1 ton of ore for the mining stage is still providing benefits (max allowable stripping ratio) and to set limits on the pit (the pit limit).
The concept of mining the selection of ways:
1. General Concept or depth
a. If the location of the selected shallow ore deposits surface
b. If the location of ore deposits in selected underground
2. The concept of economic / profit
a. Cut-off grade (COG)
b. Break-even stripping ratio (BESR)
Cut-off grade (COG) has two meanings, namely:
1. Levels of mineral deposits that still provide benefits when the sediment is mined (not required mixing mineral deposits).
2. The average levels of the lowest of mineral deposits that still provide benefits when the sediment is mined (required mixing: mixing / blending)
Cut-off grade (COG) will determine the boundaries of reserves that can be calculated by the large reserves because it would result in longer life reserves.
There are 2 things that are considered to be more economical mining efforts are:
1. Mining system in accordance with field conditions
a. Data mineralogist
b. Physical and chemical properties of ore and country rock like hardness, impermeability, etc.
2. Efficiency work
High work efficiency can be done in several ways:
a. Selecting a tool with the number and type of the corresponding
b. Coordination of the tools of good
c. Organization in accordance with these conditions
d. Employees (trained operator)
Mining the existing system in general is:
1. Mine Open (Surface Mining)
Is a mining system in which all work activities directly related to the atmosphere or the air outside. Based on the types of material mined, then open the mine divided into:
a. Open Pit / Open Cut / Open Cast / Open Mine
A mining system is applied to ore deposits containing metals. Example: Nickel Mine in Pomalla, Southeast Sulawesi, mineral Garnierite, Aluminum Mine in Deer Riau Islands, mineral Gibbsite, Boechmite, Diaspore (Bouxite), Copper Mine in Irian Jaya Earthberg, mineral Calcophyrite and Cuprite, Tambang Timah Bangka Pemali minerals in Cassiterite, etc..
b. Quarry
A mining system applied to mineral deposits industry (category C). Examples: marble stone mines in East Java Great Tulung Marble rocks, mines on the island of Buton Asphalt limestone rock asphalt, mines on the island of Karimun Granite granite rocks, etc..
c. Strip Mine
A system that is applied to mining ore deposits are located horizontal or slightly tilted. Example: Coal Mining in Tanjung Enim, South Sumatra, Ombilin Coal Mine in West Sumatra Sawah Lunto Bituminous Coal minerals, etc..
d. Alluvial Mine
A system that is applied to mining alluvial deposits. Example: Tin Ore Mining in Bangka Belitung Cassiterite minerals, Iron Ore Mine in Cilacap mineral Magnetite, Hematite, Ilmenite, etc..
Based on the way mining is done there are several ways disposal O/B is suitable for open mining, namely:
a. Back Filling, which is piled again places the former excavations had taken his ore.
b. Benching System, which is stripping O/B with the system level, this system suitable for the thick cover soil and minerals or a thick layer of coal.
c. Excavator Bucket Multy System, which cover the land disposal place that had been dug coal or place special disposal. This paring way similar to the way of Bucket Wheel Excavators (BWE), suitable for ground cover material is not soft and sticky.
d. Drag Scrapper System, this method is usually immediately followed by extractive decision after closing the land disposed of, but could also land the cover is spent first and then the new dig materials are mined, ground cover suitable for the material soft / loose.
e. Conventional ways, explore a combination of equipment (bulldozers), tool load (track loader) and transport equipment (dump trucks).
2. Underground Mining
A mining system in which all work activities not directly related to the outside air and ground operations conducted under way prior to the entrance of sinks (shaft) or tunnel help (adit). Based on the way supported underground mines are divided into:
a. For Coal
*) Longwall Methode, divided by 2 is the way forward (advancing) and the way forward (retreating)
*) Room and Pillar Methode
b. To precipitate Ore / Metal
*) Open Stope Methode, such as underground gloryhole, gophering, shrinkage stopping, sublevel stopping
*) Supported Methode, such as cut and fill, stull stopping, shrink stopping and full
*) Caving Methode, such as top slicing, sub-level caving, block caving
Comparison between 2 methods of mining are:
Open Mine Underground Mine
1. Development less
Shaft, other openings
2. Stripping O / B a lot of coal mined from the opening towards the coal layer
3. Many locations for the dumping areas are no
4. Disturbances in the stability of slopes, subsidence resulted in the installation above, poisonous gas
5. Noise, dust pollution in the affected area around the openings
6. Keep good work safety ventilation and lighting
7. The use of more free Not free
8. Productivity is influenced by the climate more in temperature rise
9. The depth of excavation is restricted SR cost O / B is not limited
10. Treatment supported reclamation costs
How to choose the best one, there are 2 things to note are:
1. The depth of sediment
a. Deposition of gold cikotok 350 m (underground mining)
b. Deposits of copper at Bingham Utah, USA (strip mine)
2. Economic considerations (beneficial or not)
The objective is to obtain maximum benefit to the mining recovery and may also be relatively safe for workers
The existence of good mining system will improve the mining recovery (MR).
MR = Comparison of sediment deposition successfully mined with an estimated according to the calculation of exploration
Why should take maximum advantage of the mining business:
Growth of a deposition is very slow / old, when compared with the speed of acquisition, therefore, in economics or wasting said unrenewable dissipation of assets or capital to do so it must be made to take the ore for high coat.
In general, if the ore that remains difficult to get it back, so the parts are left only limited to the parts that will cost high more expensive, for example gold mine cikotok/cirotan gold with levels = 9.00 g/ton was not mined.
Thus the mining business there is anything contradictory in selecting mining systems, namely:
1. With a safe, cost-expensive but not a great benefit
2. Less safe, not cost so much and benefit greatly