Mining Planning
and Design
and
Dredging and Placer Mining Part 2
Lesson 9
Objectives:
a) Student will plan a trip to do some
prospecting in Alaska.
b) Student will explain how ecology of
an Alaskan river is affected by dredging.
Surface Mining
As with any mining project, the planning
process for strip mining is based on data collected and the prospect
of making a profit. The variables that are involved in the economic
analysis may include consideration of various mining methods/equipment
combinations, mine size/equipment combination, mining method/pit
layout combinations, etc. Problems could arise in areas such
as geology, engineering, environmental sciences, and economics.
The correct mine plan will optimize the economic return using
many individuals with diverse backgrounds and training.
Jones (1977), SME Mining Engineering Handbook,
has outlined 10 major steps involved in planning and developing
a surface coalmine. These steps can take up to 10 years and require
millions of dollars of expenditure exclusive of that for actual
mine preparation and equipment purchase.
|
Salient Factors Requiring Consideration
in Mine Planning and Feasibility Studies |
| I. Information On Deposit |
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A. Geology: Overburden |
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a. Stratigraphy
b. Geologic structure
c. Physical properties (highwall and spoil characteristics, degree
of consolidation)
d. Thickness and variability
e. Overall depth
f. Topsoil parameters |
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B. Geology: Coal |
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|
a. Quality (rank
and analysis)
b. Thickness and variability
c. Variability of chemical characteristics
d. Structure (particularly at contacts)
e. Physical characteristics |
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C. Hydrology
(Overburden and Coal) |
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a. Permeability
b. Porosity
c. Transmissitivity
d. Extent of aquifer(s) |
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D. Geometry |
| |
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a. Size
b. Shape
c. Attitude
d. Continuity |
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E. Geography |
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a. Location
b. Topography
c. Altitude
d. Climate
e. Surface conditions (vegetation, stream diversion)
f. Drainage patterns
g. Political boundaries |
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F. Exploration |
| |
|
a. Historical
(area, property)
b. Current program
c. Sampling (types, procedures) |
| II General Project Information |
| |
A. Market |
| |
|
a. Customers
b. Product specifications (tonnage, quality)
c. Locations
d. Contract agreements
e. Spot sale considerations
f. Preparation requirements |
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B. Transportation |
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a. Property access
b. Coal transportation (method distance, cost) |
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C. Utilities |
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|
a. Availability
b. Location
c. Right-of-way
d. Cost |
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D. Land
and Mineral Rights |
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|
a. Ownership (surface,
mineral, acquisition)
b. Acreage requirements (onsite, offsite)
c. Location of oil and gas wells, cemeteries, etc. |
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E. Water |
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|
a. Potable and
preparation
b. Sources
c. Quantity
d. Quality
e. Costs |
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F. Labor |
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a. Availability
b. Rates and trends
c. Degree of organization
d. Labor history |
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G. Governmental
Considerations |
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|
a. Taxation (local,
state, federal)
b. Royalties
c. Reclamation and operating requirements
d. Zoning
e. Proposed and pending mining legislation |
| III. Development and Extraction |
| |
A. Compilation
of Geologic and Geographic Data |
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|
a. Surface and
coal contours
b. Isopach development (thickness of coal and overburden, stripping
ratio, quality, costs) |
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B. Mine Size Determination |
| |
|
a. Market constraints
b. Optimum economics |
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C. Reserves |
| |
|
a. Method(s) of
determination
b. Economic stripping ratio
c. Mining and barrier losses
d. Burned, oxidized areas |
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D. Mining Method
Selection |
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|
a. Topography
b. Refer to previous geologic/geologic factors
c. Production requirements
d. Environmental considerations |
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E. Pit Layout |
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a. Extent of available
area
b. Pit orientation
c. Haulage, power, and drainage systems
d. Pit demensions and geometry |
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F. Equipment Selection |
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a. Sizing, production,
estimates
b. Capital and operating cost estimates
c. Repeat for each unit operation |
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G. Project Coats
Estimation (Capital and Operations) |
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|
a. Mine
b. Mine support equipment
c. Office, shop, and other facilities
d. Auxiliary facilities
e. Manpower requirements |
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H. Development
Schedule |
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a. Additional
exploration
b. Engineering and feasibility study
c. Permitting
d. Environmental approval
e. Equipment purchase and delivery
f. Site preparation and construction
g. Start-up
h. Production |
| IV. Economic Analysis |
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A. Sections
III and IV repeated for various alternatives |
| |
Major Steps in Surface Mining
Development
Jones (1977), SME Mining Engineering Handbook,
has outlined 10 major steps involved in planning and developing
a surface coalmine. These steps can take up to 10 years and require
millions of dollars of expenditure exclusive of that for actual
mine preparation and equipment purchase.
I. Assembly of the Mining Coal Package
1.Leasing Acquisition
2. Mapping the area
3. Drilling program
4. Surface drilling rights acquisition
5. Drilling, sampling, logging, analysis
6. Mineral evaluation (determination on commercial quantities
present)
7. Drilling on closer centers (development drilling)
8. Sampling, logging analysis
9.Surface Acquisition
II. Market Development
1. Market survey
2. Potential customer identification
3. Letter of intent to develop and supply
4. Contact negotiation
III Environmental and Related Studies
1. Initial reconnaissance
2. Scope of work development
3. Implementation
4. Environmental impact report
5. Environmental monitoring
IV. Preliminary Design, Machine Ordering
1. Conceptual mining development
2. Economic size determination
3. Mining system design, layout and development
4. Equipment selection
5. Stripping machine ordering
6. Mine plan development
V.NEPA Process (National Environmental
Policy Act of 1969)
Identification of lead agency for Environmental
Impact Statement (EIS)
Draft EIS
EIS review and comments
EIS hearing and record
Federal EIA review
Council on Environmental Quality filing
Mining and /or reclamation plan approval
VI. Permits
State water well rights appropriation permits
State special use permit, such as a reservoir
State mining permit
State industrial siting permit
Federal NPDES permit
US Forest Service special land use permit
VII. Design and Construction
Preliminary design and estimation
Material ordering and contracting
Water well development
Access road and site preparation
Railroad construction
Power supply and installation
Facilities and coal handling construction
Warehouse building and yards
Coal preparation and loading facilities construction
Overland conveyor construction
VIII. Mining Preparation
Stripping machine
Loader erection
Support equipment readying
Manpower recruitment and training
IX Production Buildup
X. Full Production
***Source: Jones, SME Mining Engineering Handbook,Matthew
J Grebar and Thomas Atkinson,1977.Referenced to Chapter 13
PUT STRIP MINING PLANNING AND DESIGN CHART HERE
PAGE 1301
Alternative Stripping
Methods
Area Dragline Method- The area/dragline method involves opening an
initial box cut, removing the coal exposed in the box cut and
then placing the overburden from the next longitudinal cut into
the mined out, box cut area. The procedure is then repeated on
a cut-by-cut basis. The method is also referred to as "deep
plowing."
This operation is generally employed in flat to moderately dipping
coal seams with constant overburden depths. This works best in
areas where the coal and overburden reach economic limit in a
few cuts.
The advantage of the dragline method is
the flexibility in varying the operations that the stripping
shovel can handle. The dragline can handle varying overburden
depths, characteristics, and multiple seams by changing modes.
It may cause some loss of machine productivity but the need for
additional equipment is decreased.
PICTURE NEEDED
HERE FOR AREA DRAGLINE
Modified Open Pit-
Modified open pit or terrace mining is generally used in thick
seam properties with low stripping ratios. In these operations,
the seams are generally flat lying, gently dipping and rolling.
This method often puts the overburden in off-site storage. Coal
is then removed from the initial pit area. The next cut is taken
in the direction of the mine advance and the over burden is hauled
around to the existing pit and dumped. The coal is removed and
the haul back process is repeated as the pit advances.
Block Area/Dozer-Scraper Method- The block area method uses construction-type equipment
and was first conceived in the mid 70's as an alternative to
the dragline method. Because the dragline equipment was so difficult
to procure, the dozer/scraper method began to take hold. This
method takes advantage of the scrapper's ability to move material
over a short distances at low costs and the scrapper's ability
to elevate material overstep grades for short distances at reasonable
costs.
References:
**This article was adapted from Matthew
Hrebar and Thomas Atkinson. SME Mining Engineering Handbook,
2nd Edition, Volume 2. (Littleton, Colorado:
Society for Mining, Metallurgy, and Exploration, Inc., 1992),
pp. 1298-1303.
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