Mine D 1 Chap 5

This document discusses the design of waste dumps for mining operations. It explains that waste dumps are used to dispose of low-grade material removed from pits. The first step is selecting suitable dump sites based on factors like pit size/location, topography, waste volumes, and reclamation needs. Dumps are then designed in phases to minimize haul distances. Stability depends on site topography, construction method, material properties, foundations, and external forces. Dumps can be constructed by end-dumping or layered in lifts.

Uploaded by

Mekonen

We take content rights seriously. If you suspect this is your content, claim it here.

Available Formats

Download as PPTX, PDF, TXT or read online on Scribd

0% found this document useful (0 votes)

58 views33 pages

Mine D 1 Chap 5

Uploaded by

Mekonen

We take content rights seriously. If you suspect this is your content, claim it here.

Available Formats

Download as PPTX, PDF, TXT or read online on Scribd

You are on page 1/ 33

AKSUM UNIVERSITY SHIRE

CAMPUS
SCHOOL OF MINES
DEPARTMENT OF MINING ENGINEERING

MINE DESIGN ONE

Compiled By:- Kibrom A.

03/26/2024 Aksum university shire campus Faculty of Mines 1
Compiled By Kibrom Assefa T.
Chapter FIVE
Waste dump design
• A waste dump is an area in which a surface Mining operation can
dispose of low grade and/or barren material that has to be removed
from the pit to expose higher grade material.
• In some instances, material has to be removed for other indirect
reasons, such as pit wall stabilization and for haul road
construction.
• Mining waste can be defined as a part of the materials that result
from exploration, mining and processing of substance governed by
legislation on mines and quarries. Mining operation also produce
diverse kind of potentially hazardous waste.
• Mining Waste: Mining operation brings out all sorts of unwanted
materials, which is known as mining waste.

03/26/2024 Aksum university shire campus Faculty of Mines 2

Compiled By Kibrom Assefa T.
Con’t …
• The first step in designing a dump is the selection of a site or sites
that will be suitable to handle the volume of waste rock to be
removed during the mine's life. Site selection will depend on a
number of factors, the most important of which are:
1) Pit location and size through time.
2) Topography.
3) Waste rock volumes by time and source.
4) Property boundaries.
5) Existing drainage routes.
6) Reclamation requirements.
7) Foundation conditions.
8) Material handling equipment.

03/26/2024 Aksum university shire campus Faculty of Mines 3

Compiled By Kibrom Assefa T.
Con’t …
• All of these parameters will be considered during the site selection process.
Once a site or number of alternative locations have been selected, the
designing of the dumps can commence, using the same points utilized in
defining the best potential dump locations.
• The objective of dump planning is to design a series of waste disposal
phases that will minimize the horizontal and vertical distances between the
source and the disposal area. Since material handling costs are usually the
largest single component of the mining cost, well designed dumps play a
very important and critical role, affecting the expense of the total operation.

03/26/2024 Aksum university shire campus Faculty of Mines 4

Compiled By Kibrom Assefa T.
Con’t …
• Two of the most important parameters affecting dump design have
been set before any design effort commences:
1) The pit location and size through time and
2) The waste production schedule and source location.
• These two parameters define where the dumps can start, how fast
they will advance, and the ultimate volume that the disposal area
must contain.
• The location Where dumping can commence may not necessarily
be outside of the pit limits. In some instances, internal dumping
May be the most economical and practical method of establishing
haul roads to the disposal area or to later pit phases.
• Also, as an alternative, it may be wiser to dump short and re handle
the material in the future if the economic benefits of this can be
demonstrated.
03/26/2024 Aksum university shire campus Faculty of Mines 5
Compiled By Kibrom Assefa T.
Con’t …
• This can affect the pit design in the sense that later phases adjacent
to the dumps could have higher ratios than the original design.
Therefore, these areas should be examined in more detail and the
haulage cost savings gained by dumping short compared to the
potential ore reserve loss.

03/26/2024 Aksum university shire campus Faculty of Mines 6

Compiled By Kibrom Assefa T.
S TA B I L I T Y O F M I N E WA S T E D U M P S
The overall stability of mine waste dumps is dependent on a
number of factors such as:
1) Topography of the dump site.
2) Method of construction.
3) Geotechnical parameters of the mine waste.
4) Geotechnical parameters of the foundation materials.
5) External forces acting on the dump.
6) Rate of advance of the dump face.
• All of these factors combine in various ways during the life of a
mine waste dump to aid in the stability of the dump or to contribute
to its instability.

03/26/2024 Aksum university shire campus Faculty of Mines 7

Compiled By Kibrom Assefa T.
Con’t …
• The choice of dump sites and their topography usually is limited to
within an economic distance from the mine and, since rearranging of
site topography is rare, the topography usually becomes a fixed
condition.
• Mine waste dumps are usually constructed by one of two common
methods: in lifts or layers or by end-dumping.
• End dumping is a controlled failure process where the waste
material is deposited forming a slope at or close to its angle of
repose and the factor of safety is accordingly close to one. Since the
front face is always advancing during the life of the dump, the
slopes are not stabilized by flattening with conventional
earthmoving equipment until closure of the dump.
• The mine waste dumps constructed using an end-dumping technique
are sometimes referred to as "built from the top,"
03/26/2024 Aksum university shire campus Faculty of Mines 8
Compiled By Kibrom Assefa T.
Con’t …
• whereas, layered dumps are said to be constructed "from the
bottom up."
• Layered dumps can be controlled, which adds significantly to their
overall stability; however, they require a relatively gently sloping
topography and usually entail a longer haul distance in the early
years of the mine.
• Layered dumps are preferred where weak foundation conditions
exist, since the load application can be controlled to allow for
strength gains by consolidation and pore pressure dissipation.

03/26/2024 Aksum university shire campus Faculty of Mines 9

Compiled By Kibrom Assefa T.
Con’t …
• The geotechnical properties of the mine waste and the foundation
material are major factors in determining the overall stability of a
mine waste dump.
• Such characteristics as strength, friction angle or cohesion, and
gradation are parameters determining the type of analyses that
would be selected to solve or define the stability condition. Each
mine waste dump site presents a unique set of problems and would
have to be analyzed as a separate and distinct case; however, certain
general conclusions may be drawn based on some simplifying
assumptions.
• For instance, coarse frictional material on a competent foundation
with a slope angle less than or equal to the material's angle of
repose may be dumped to practically unlimited heights and would
represent the safe side of the problem.

03/26/2024 Aksum university shire campus Faculty of Mines 10

Compiled By Kibrom Assefa T.
Con’t …
• External forces, such as water and earthquakes, often play a
decisive role in the stability of a mine waste dump and, therefore,
should be carefully considered in the analysis. Of the two,
earthquake or seismic forces are a relatively straightforward factor
that can be readily accommodated in most stability analyses by
determining the location of the mine waste dump in relation to
seismic zones and inputting the proper seismic coefficient into the
analyses as an additional horizontal force.
• Topography has a direct influence on dump stability in different
ways. Mine dump instability on steep terrain may be due to the
difficulty in achieving adequate dump density and therefore the
maximum shear strength of the material Other problems include
slope regions with increasing slope angles in the vicinity of the toe
or side flanks.

03/26/2024 Aksum university shire campus Faculty of Mines 11

Compiled By Kibrom Assefa T.
The dumping method of material can be used to classify
dumps into five basic types:
• End dumping-dumping rock over dump face resulting in some
particle size segregation down slope towards the toe of the rock
pile, with particle size generally increasing
• Push dumping - dumping from trucks, followed by leveling and
pushing by tractors and shovels resulting in particle size
segregation: finer at the top and coarser at the toe of the dump slope
• Free dumping or plug dumping - dumping in small piles on the
surface of the rock pile, grading the material, and compacting in
layers or lifts resulting in dense layers with no real particle size
segregation

03/26/2024 Aksum university shire campus Faculty of Mines 12

Compiled By Kibrom Assefa T.
• Dragline spoiling-deposited on the surface without construction of
lifts and minimal compaction resulting in dense layers with no real
particle size segregation because of relatively low overall height of
the spoil piles, typically used in coal mining
• Mixing of waste rock with tailings.

Con’t …
03/26/2024 Aksum university shire campus Faculty of Mines 13
Compiled By Kibrom Assefa T.
WASTE DUMPS CLASSIFICATION

 Waste dumps are broadly classified in to two, those are

1. water-impounding and
2. Non impounding.
• If the dump is situated across natural drainage so as to allow
continuous or intermittent accumulation of water or saturated waste
behind the structure, it is classified as impounding. If water cannot
accumulate, it is classified as non impounding.
• In addition to impounding and non impounding status and durable
vs. nondurable material, waste dumps can also be classified
according to configuration. composition, and environmental
sensitivity.
Classification of waste dump according Configuration
• Natural topography provides several options for siting dumps. The
dumps may be placed on relatively level ground.
03/26/2024 Aksum university shire campus Faculty of Mines 14
Compiled By Kibrom Assefa T.
Con’t …

 In valleys, on side hills, or along ridge tops. The location provides a

corresponding adjective that is helpful in creating a mental picture
of the structure.
Heaped: A heaped or fan dump is constructed on relatively flat
terrain. The final elevation of the crest of the dump may be
achieved by compacting successive layers of fill with
interconnecting ramps established between the original ground
elevation and the current lift.
• Alternatively. the structure can be completed by extending the top
of a ramp laterally in a single lift. If the lift is long relative to its
width, it is referred to as a finger dump.
• Valley Fill: Waste may be placed in a valley by continuous
dumping on the downstream face from the planned final elevation.
Valley fills may also be constructed from the bottom up using
compacted lifts.
03/26/2024 Aksum university shire campus Faculty of Mines 15
Compiled By Kibrom Assefa T.
Con’t …