1. CHAPTER NO.1
INTRODUCTION TO ORE BODY
1.1 INTRODUCTION TO ORE:-
Ore is generally understood to be any naturally occurring , in place , mineral
aggregate containing one or more valuable constituents that may be recovered at a
profit under existing economic conditions.
1.2 ORE BODY:-
A Dictionary of Earth Sciences defines the ore body Accumulation of minerals,
distinct from the host rock, and rich enough in a metal to be worth commercial
exploitation.
The general name for an accumulation of ore in any shape. An ore body may
correspond to an ore deposit, but more often the deposit includes several ore bodies.
The boundary between an ore body and the enclosing rocks may be distinct and
discernible to the eye. On the other hand, it may be indistinct, with a gradual
transition from the ore body through a zone of impregnated low-grade ores and
weakly mineralized rocks to the enclosing rocks. When indistinct, the boundary of the
ore body is established during the sampling process, based on the minimum allowable
content of metal or mineral in the ore.
Three groups of ore bodies are distinguished by shape: isometric, flat, and elongated
in one direction. Isometric ore bodies are accumulations of mineral substance that are
approximately equal in all measurements. They include stocks, stock works, and
pockets, relatively small accumulations of ore that are isometric in shape and usually
not more than 1–3 m in cross section.
Flat ore bodies—sheets, veins, and lenses—have two long dimensions and one short
dimension. The sheet, the most common shape in which sedimentary deposits occur,
is a tabular body separated from other rocks by bedding planes. A distinction is made
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2. between simple sheets and complex sheets, which have rock interlayer‘s. Sheet like
deposits differ from sheets in their smaller dimensions, discontinuity, and lesser
stability of thickness. They are typical of weathering deposits.
Veins are ore bodies formed when a mineral substance fills fracture cavities or when
there is met somatic substitution of mineral substances for rocks along cracks. The
plane of contact between the vein and the enclosing rocks is called the selvage. The
zones of mineralized lateral rocks of veins create a contact metamorphic aureole that
sometimes contains industrial concentrations of valuable components. Where the
minerals that fill the veins are unevenly distributed, there is an alternation of sections
rich and poor in valuable components; the rich sections in the body of the vein are
called ore shoots. Ore shoots may be morphological or concentrated. The former are
formed by bulges in the vein, whereas the latter are zones having an increased
concentration of valuable components unrelated to change in the morphology of the
ore body but rather caused by local alterations of the physicochemical parameters of
ore deposition. The latter are sometimes related to the ability of the ore-enclosing
rocks to react chemically with solutions. Sometimes they result from a sharp change
in the temperature and pressure of solutions, the change leading to a large-scale
accumulation of ore minerals.
A lens is a lenticular geological body that tapers out markedly in all directions; its
thickness is slight compared to its length. In terms of morphology, lenses and
lenticular beds are transitional formations between isometric and flat ore bodies.
Ore bodies elongated in one direction are called ore pipes or pipes. Ore pipes are oval
in cross section. They form when an ore substance from magmatic melts or
hydrothermal solutions is concentrated; the melts or solutions penetrate from the
abyssal parts of the earth‘s crust along the line where tectonic fractures intersect or
along fractures that intersect easily penetrated rock strata. Sometimes, when melts or
hot vapors and gases break through a bed of rock, diatremes are formed; examples are
the diamond-bearing kimberlite pipes of Siberia and South Africa. There are ore pipes
composed of copper, lead-zinc, and tin; they are up to several kilometers long, and
their width in cross section varies from a few meters to several hundred.
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3. 1.3 MINERAL:-
Usually inorganic substance which occurs naturally and typically has a crystalline
structure whose characteristics of hardness, luster, color, cleavage, fracture, and
relative density can be used to identify it. Each mineral has a characteristic chemical
composition. Rocks are composed of minerals. More loosely, certain organic
substances obtained by mining are sometimes termed ‗minerals‘
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4. CHAPTER NO.2
ORE BODY MODELING AND ITS TYPES
2.1 INTRODUCTION:-
Production geologists use information they obtain from sampling, testing, mapping
and observation to determine the most efficient and effective mining techniques, as
well as to identify the grade (amount of mineral) in the ore. In gold and silver mining,
grade is reported as grams per ton. Copper grade is reported as a percentage. It is
important to know the grade to determine which rock is sent to the plant for
processing and which rock is sent to the waste rock storage area.
By using this data and complex computer programs to more accurately define the ore
body, mine engineers can determine mining methods, design blast patterns, design dig
patterns, and maximize the safety and efficiency of production - as well as determine
how the ore should be processed.
Geologists also use drilling and sampling data to identify wet areas. Water can cause
major problems in both open pit and underground mines. If areas of high water
content can be avoided or planned for in advance, we can reduce safety risks, costs
and production interruptions.
2.2 WHAT IS MODEL:-
A geological model is a representation or an interpretation of a mineral deposit. The
deposit could be any commodity, including gold, iron, or coal. Prior to the 1970‘s
many geologists and engineers would build 3D models of the ore body and mine
workings to help visualize or understand the deposit. The model would often be a set
of Perspex cross sections hanging in a wooden frame.
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5. Computers have given us the power to build those models electronically, and view
them dynamically in 3D or in sections and plans. The models can be updated as new
data becomes available and most importantly guide mine planning. Computer models
also produce volume and grade reports that reconcile production information and
measure mining efficiency and performance.
A software model is a numerical arrangement of data that can readily be displayed
and used for volumes. Computer models typically represent geology as so called 2D
or 3D models.
Ore bodies can be categorized in many ways, but for this paper we consider three
different categories, as shown in Table.
Table 1.1 three categories of ore body
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6. 2.2.1 2D MODEL:-
In a 2D model a square or rectangle grid or mesh is placed over the area of interest. Z
values or elevations are then assigned to centers of the mesh. The mesh is a pattern in
XY space. So Z is stored at XY locations, hence the term 2D model. The Z value is
stored at X and Y locations. The Z values represent attributes of the geology, such as
topography (Figure 1), or nickel content or thickness.
Figure 2.1 Typical 2D model of topography
2.2.2 3D MODEL:-
Many surface users will be familiar with 3D models. Here the model values or
attributes (called Q for quality) are stored at the centered of a block. the block has a
location and size in XYZ and Q is stored is 3D space, hence the term 3D model as
shown in figure shows a surface block model Q values such as gold grade, mill cost or
mill recovery are held in each block. In Figure 2 the block colour reflects a block
attribute. Block models are ideal for complex ore body shapes. Typically these ore
bodies have been formed by intrusion and/or faulting and the ore body interpretation
is usually based on rock type, alteration or grade using wire framing. Interpretations
are made on sections and these interpretations are then joined in a wire-framed shape.
Figures 3 and 4 show such an interpretation.
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7. Figure 2.2 3D block model
Figure 2.3 Wire frames (blue) connect outlines (white)
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8. Figure 2.4 Solid display
In 3D models the wire frame shapes are filled with blocks and sub-blocks to represent
the ore body. By selection of a reasonable block size, which trades accuracy and
speed, the ore body can be well represented. These blocks are then filled with attribute
values (Q) from the drill whole data. Typically this involves detailed variogram
analysis and selection of appropriate variogram parameters. Domain control such that
the grades within a wire frame are used to determine the blocks in that frame are a key
feature of the process. The attribute could be gold, silver or SG. Figure shows a block
model in cross section, the colours represent gold values. The ore body has been cut
with a barren dyke represented by the grey blocks.
Figure 2.5 Sub blocked model showing use of small sub blocks on edges
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9. 2D models are ideal for thin or layered deposits, such as coal, bauxite and phosphate.
These deposits are often extensive in area. For example a typical Hunter Valley coal
mine would be 8,000 meters by 10,000 meters in lateral extent. While the total
Sydney coal basin covers an area from Newcastle to Wollongong and west to Lithgow
(approximately 200kms x 300kms). Within a single mine there could be 40 seams,
which vary in thickness from 0 meters to 10 or 20metres. In modeling these layered
deposits, the seams are modeled as a series of linked or associated surfaces. For a coal
seam such as the Bayswater a number of individual 2D models or surfaces are
created. In Minex a naming convention is used consisting of the seam prefix and an
extension suffix. Usually the seam suffixes are kept brief, so Bayswater is abbreviated
to BAY. The standard Minex naming convention is shown in Table 2. The common
prefix BAY associates all these surfaces together while the standard suffix endings
allows Minex to treat the model correctly for volumetric, tonnage or cross section
purposes.
Figure 2.6 Floor elevation model for a coal seam (yellow) with topography (green).
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10. 2.2.3 2D VERSUS THE 3D APPROACH:-
There are several deposit characteristics where the 2D modeling is preferred. These
characteristics are: The thickness of the ore body seams or veins may necessitate a
high-resolution block model (very small or thin blocks) to adequately represent the
ore body. Coal, phosphate and literates are either thin or variable in thickness. Figure
2.8 shows an example coal seam cross section. This deposit has a typical mixture of
thick and thin seams, which vary from 1cm to 3metres in thickness. The seam
thickness is typically measured to +/- 1cm accuracy. As thickness is equivalent to
tonnage and tonnage is equivalent to dollars, the thickness model must be accurate.
Even though computers are steadily increasing in speed, the time required for
processing a block model with a very large number of blocks may be impractical. 2D
modeling due to its infinitely variable block size is ideal for these deposits.
Figure 2.8 shows an example coal seam cross section
Typical coal deposits in cross sections Sedimentary deposits are often large in lateral
extent (measured in tens of kilometers) and block models become too large and slow.
Traditional 3D polygon and solids modeling techniques may not be able to adequately
project the detailed fault and shear structures through a range of veins or seams.
Extending such structures manually through each seam or vein may be tedious and
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11. impractical. A seam or vein modeling system has the facilities to define structures and
propagate them through the model. The 2D modeling approach uses rules that ensure
that ordering of the seams or veins is rational (stratigraphic). This avoids seams
crossing or overlapping. Rules also allow for seam splitting. The rules system also
makes automatic modeling of all seams relatively simple. There is no need to
manually wireframe borehole-to-borehole data. The automatic modeling and rules
based approach means new data can be efficiently added to the model. In other words
the model can be easily maintained.
2.2.4 HOW DO WE GENERATE THE 2D SURFACES OR MODEL?
In Minex the seam data is held in the drill holes as intervals or picks. These intervals
provide thickness, moisture, ash and steam elevation data at the drill hole location. By
compositing quality data (such as ash or moisture) across the interval the average
quality is defined. Figure 9 shows a borehole database with the seam intervals in
different colours. Various algorithms are used to generate a model from this data.
Example algorithms are kriging, inverse distance and trend surface techniques. For
example in Figure 9 the light blue data points can be connected into a thickness model
or surface.
Figure 2.9 Borehole database seam data
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12. In 2D modeling algorithms the seam name in the borehole is critical. If the name is
correct then the modeling is virtually automatic. The seam name in the drill hole is
analogous to the domain name in a 3D block model. When we determine the block
value we only use the correct domain data, we don‘t want to use data from another
domain. The seam name has the same importance in 2D modeling. We only use seam
A data to determine the values in the seam A model. The simplicity of the naming is a
major advantage over wire framing. Wire frames are built manually by connecting
drill hole data on a series of sections. Typically the wire frame is built in the office
after all the analytical data is collected. In coal however, the litho logy is more black
and white and often the field geologist can assign the seam name in the field while
logging or can assign it from down hole geophysical logs, such as density, which
differentiate between coal and waste. Once the seam(s) is defined the model values
(elevation, thickness, ash) are estimated by scanning the surrounding drill hole data.
Figure 10 shows an area around three drill holes. The model values vary from 0.48
meters at the top of the sheet to 0.35metres at the bottom. Each model value (purple)
is stored at the centered of the grid cell while the borehole data value is sampled at the
red drill hole location.
Figure 2.10 Seam thickness model and drill hole data
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13. In layered deposits Minex links the various 2D surfaces into a 3D model. For
examplethe seam floor model locates the seam in XYZ space; the thickness model
defines thecoal volume and the RD model converts volume to tones. In a 3D block
model, volume is just a count of the cubes inside say a pit. In a 2D model volume is
simply a count of the columns inside the pit. However in a 2D model each column has
a variable thickness or height. So where a 3D model is based on lots of regular cubes
a 2D model is based on a pattern of regular bases or grids with irregular heights or
thickness. Thus for thin or large extensive layered geology the 2D model is more
accurate then the 3D model.
2.2.5 VEIN MODEL:-
The standard 2D model stores the Z values in planar XY space. That is X is usually
measured horizontally from west to east and Y is measured horizontally from south to
north. Z (or Q) is stored as an offset from this plane. For thin steeply dipping ores
such as nickel or gold veins, vein modeling can be used. Vein modeling uses a
coordinate system where X and Y are along a plane parallel to the ore body and Z is
perpendicular to the plane. For measuring thickness (and hence tonnage) this
orientation is useful as the thickness measured is now true thickness not apparent
thickness. Thus variography and other statistics are more robust. Figure shows a vein
model system. Here the ore is near vertical and the footwall (orange) and hanging
wall (yellow) are modeled as 2D grids. To give reasonable resolution the XY
coordinates are rotated to a vertical plane. Both models were created as surfaces from
the borehole vein intersect. Careful wire frame digitizing was not required. Using
these surfaces the vein can be converted to a conventional block model. The footwall
and hanging wall are then used as the limit surfaces. Examples of these blocks are
shown in Figure.
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14. Figure 2.11 Example vein model
Figure 2.12 Block model based on vein surface
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15. 2.3 TIE IN PATTERN:-
A tie in pattern can be generated using one of the standard templates, or you can
select holes/tie in lines individually to generate a customized pattern.
2.4 STOPS:-
Underground mine workings, for example: declines, development drives and draw
points. A solid model is creating by forming a set of triangles from the points
contained in the string. These triangles may overlap when viewing in plan, but do not
overlap or intersect when the third dimension is considered. The triangle in a solid
model may completely enclose a structure.
Creating of solid models can be more interactive than the creation DTMs, although
there are many tools in Surpac vision which can automate the process the following
diagram shows an example of a solid model (design decline and ore body). Make use
of the 32,000 numbers available to number objects as it makes them easier to edit.
Terminology
A solid model is made up of a set of non-overlapping triangles. These triangles from
objects that may have a numeric identifier between 1 and 32,000.
Objects represent discrete features in a solid model. For example, in the diagram
shown above, the decline and the ore bodies all have different object numbers as they
represent different features. However, features such as ore bodies can consist of
discrete pods, and you may want to give these pods the same object number to
indicate that they are from the same structure. In this case, each discrete pod must
have a different trisolution number. A trisolution is a discrete part of an object and
may be any positive integer. Object and trisolution numbers give reference to all the
objects contained in a solid model. An object trisolution may be open or closed. A
resolution is open if there is a gap in the set of triangles that make up the trisolution.
An object may contain both open and closed trisolution. The reason for treating
objects as open or closed trisolution. The reason for treating objects as open or closed
are A closed object can have its volume determined directly by summing the volumes
of each of the triangles to an arbitrary datum plane.
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16. A closed object always produces closed strings when sliced by a plane. A closed
object could be used as a constraint in the Block Modeling module. An open object
cannot provide the same capabilities: when sliced by a plane the strings it produces
may be open or closed or both.
2.5 WHAT IS THE SOLID MODEL?
A Solid model is a three-dimensional triangulation of data. For example, a 3DM is a
solid object formed by wrapping a DTM around strings representing sections through
the solids. Solid model are based on the same principles as Digital Terrain Models
(DTMs), used in Surpac software for many years. You may also have heard solid
models referred to as `3DMs‘ or a `wire frame model‘. Solid models use triangles to
link polygonal shapes together to define a solid object or void the resulting shapes
may be used for following.
Visualization
Volume calculation
Extraction of slices in any orientation
Intersection with data from the geological database module
A DTM is used to define a surface. With Surpac software, creating a DTM is
automatic. Triangles are formed by connecting groups of three data points together by
taking their spatial location in the X – Y plane into account. The drawback of this
type of model is that it cannot model a structure that may have fold backs or
overhangs for example Geological structure.
2.6 BLOCK MODEL:-
The Surpac three dimensional Block Model is still very simple to use and understand,
but is significantly faster in its creation, and modeling parameters can be added and
modified at any time. The Surpac Block Model is a form of database. This means that
its structure not only allows the storage and manipulation of data, but also the
retrieval of information derived from that data. It differs from a more traditional
database, in that data stored are likely to be interpolated value, rather than true
measurements. Another major difference is that these values may be spatially
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17. referenced as well as being spatially related. A third important this makes dynamic
operations such as coloring of attributes possible but imposes significant memory
overheads.
For example, consider the Geological database. Records have spatial attributes which
relate them to a spatial position. However, the converse does not necessarily hold as
spatial positions are not necessarily related to a record in the database.
The Block Model portions space into an exhaustive set of blocks, each being related
to a record. The records may be spatially referenced, that is, information may be
retrieved for any point in space, not just for points that have been explicitly measured.
This spatial referencing allows the addition of a number of operators to the querying
capabilities of the database manipulation scheme, namely spatial operators such as
INSIDE and ABOVE, which may operate on solids and surfaces. Outside and below
may be built using the NOT logical i.e. NOT INSIDE or NOT ABOVE.
The Block Model comprises of a number of component:
Model Space
The model space is a cuboids volume outside of which nothing exists in terms of the
Block Model.
Attributes
The properties of the model space that are to be modeled are termed attributes. These
attributes may binomial, ordinal, interval or ratio measurement expressed as numeric
or character data. Attributes may also be calculated from the values in other attribute
fields, for reporting and visualizing.
Constraints
Constraints are the logical combinations of spatial operators and objects that may be
used to control the selection of blocks from which information may be retrieved and/
or into which interpolation may be made. Constructed may be saved and have file
extensions of .CON.
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18. The model itself is a binary image constructed in the model space and defined by the
existence or non-existence of blocks. Model files will have file extension of MDL.
The Block Model may be applied to any situation where properties of a volume of
space are to be modeled in terms of the distribution of values through that space.
2.6.1 BLOCK MODEL CONCEPTS:-
The following terms are used in Surpac Vision model definition:
Origin
The origin of the model is the lower, front, left hand corner (i.e. the minimum Y, X
and Z coordinate) of the model expressed in X, Y and Z Cartesian coordinate. The
origin is the anchoring point from which rotation involving the Bearing, Dip and
Plunge are to be performed.
Extent
The extent of model is the dimensions of the model in the Y, X and Z directions.
For example, if a model was to cover the following area:
3000mN to 3650mN 1500mE to 2100mE to 120mEl to 270mEl
The origin will be: Y=3000 X=1500 Z=120
And the extent of the model will be: Y=650 X=600 Z=150
Bearing
The bearing of the model is the horizontal angle in degrees of the direction of the
major axis of the model. A bearing of zero indicates a non-rotated model where the
major axis of the model is in a north-south orientation.
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19. Dip
The dip of the model is the vertical angle of the blocks in degree from the horizontal
in a direction perpendicular to the bearing of the model. A negative dip is an angle
below the horizontal to the right when looking along the bearing of the model. A dip
of zero indicates horizontal blocks normal to the bearing of the model.
Plunge
The plunge of the model is the model is the vertical angle of the blocks in degree from
the horizontal along the bearing of the model. This can also be referred to as the tilt
the model. A negative plunge is an angle below the horizontal when looking along the
bearing of the model. A plunge of zero indicates horizontal blocks along the bearing
of the model.
User Block Size
The block size in the Y, X and Z directions. The user block size is used as the
reporting unit for the Block Model. The user block is also the block size upon which
interpolation is performed. The user block size will depend on the Model purpose (i.e.
Grade Control, Resource Calculation, Pit Optimization) with reference to the data
spacing.For example, what block size is appropriate for a prospect drilled on a 100m x
100m pattern, which is to have a resource estimate completed? It would not be
appropriate to set this model up with a block size of 5x5x5,as the small blocks won‘t
give a ``better‘‘ estimate of the resource, as the original data is widely spaced.
Perhaps, 25x25x10 may be more realistic (i.e. one –third to one-quarter of the sample
spacing).
Maximum sub-blocks per side
The maximum number of blocks along each side of the model. This number must
always be 2 to the power of an integer. (e. g 2,4,8,16,32,64,128,256,512)
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20. This value will need to satisfy a base resolution. For example used previously: extents
Y=650 X=600 Z=150 user block size 25x25x10
This number of blocks along each side will be 26x24x15 (extent divided by user block
size). This means that the base resolution will be 32 (the number greater than the
maximum number of blocks and is 2 to the power of something). If we wish to allow
sub-blocking (the sub-dividing of blocks), the resolution will need to be greater than
base resolution. For example: if maximum sub-blocks per side = 64 smallest sub-
block = 12.5x12.5x5 if maximum sub-blocks per side= 128 smallest sub-
block=6.25x6.25x2.5
In this way we find it possible to fill a model with interpolated values calculated at a
user block size, .i.e. user block size 25x25x10 and still constrain the data within
geological envelopes that are able to be sub-blocked to smaller sizes i.e.
6.25x6.25x2.5. This becomes important when considering the size of the model and
the number of calculations to be performed to fill the model.
2.6.2 BLOCK AND ATTRIBUTES:-
The centroid of each block defines its‘ geometric dimensions in each axis, i.e. its
coordinates, Y, X, and Z.Each block contains attributes for each of the properties to
be modeled. The properties or attributes may contain numeric or character string
values. Blocks may be of varying size defined by the user once the block model is
created.
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21. Figure 2.13 Block model of oil sands coloured by attribute values (bitumen).
2.6.3 CONSTRAINS:-
All Block model functions may be performed with constraints. A constraint is a
logical combination of one or more spatial objects on selected blocks. Objects that
may be used in constraints are plane surfaces, DTMs, solids, closed strings and block
attribute values. Constraints may be saved to a file for rapid re-use and may
themselves be used as components of other constraints. Blocks meet a constraint (e.g
below a DTM as in the figures below) if its centroid meets that constraint. This is true
even if part of the block is above the DTM.
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22. Figure 2.14 Unconstrained block model in relation to a DTM surface
Figure 2.15 Same block model but constrained by the topography (DTM).
2.6.4 ESTIMATION:-
Once a Block model is created and all attributes defined, the model must be filled by
som estimation method. This is achieved by estimating and assigning attribute values
from sample data which has X Y Z coordinates and the attribute values of interest,
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23. The estimation methods that may be used are
Nearest Neighbor Assign the value of the closest sample point to a block
Inverse Distance Assign block values using an Inverse Distance estimator
Assign Value Assign an explicit value to blocks in the model
Ordinary Kriging Assign block values using Kriging with Variogram parameters
developed from a Geostatistical study
Indicator Kriging Functions concerned with a probabilistic block grade distribution
derived from the kriging of indicators
Assign from String Assign data from the description fields of closed segments to
attribute values of blocks that are contained within those
segments extended in the direction of one of the principal axes
(X, Y or Z)
Import Centroids Assign block values from data in a delimited or fixed format text
file
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24. CHAPTER NO.3
THAR COAL FIELD
3.1 INTRODUCTION:-
District Tharparkar comprising of 4 Talukas i.e. Mithi, Chachro Diplo & Nangarparkar
having population of 914291 souls, as per census 1998, is spread over an area of
4,791,024 acres (19638sq: Kms).This District with present boundary has come into
existence on 02-12-19990 as Thar. Prior to this the present geographical area was a sub-
division of old District Tharparkar (Mirpurkhas) it was bifurcated into 2 Districts i.e.
Mirpurkhas & Thar @ Mithi. The name of Present District was re-notified as
―Tharparkar‖ on 19-10-1993. The head quarter of this District Mithi which is situated at
distance of 150 Kms. South / East of Mirpurkhas. It is situated in 24-26 North latitude
and 69-51 East Longitude. The boundaries of this District are as under.
3.2 HISTORICAL BACKGROUND:-
It was in 1843 when Sir Charles Napier Became victor of Sindh and this part were
merged into Katchh political agency in Hyderabad collect orate later on in 1858 the entire
area became part of Hyderabad. Subsequently in 1860 it was renamed as ―Eastern Sindh
frontier‖ with its Head Quarter Umerkot controlled by Political Superintendent. In 1882 it
was renamed as district and it is administrative head was Deputy Commissioner. Lastly in
1906 Head Quarter of the district was shifted from Umerkot to Mirpurkhas. Finally this
District was created in 1990. This district is specially name according to geographical
conditions, i.e. ―Thar & Parkar‖. ―Thar‖ means desert while ―Parkar‖ is rocky & hilly
park.
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25. 3.3 GEOGRAPHICAL FEATURES:-
(i) There is no stream fresh river in the district. However, in Nagarparkar there are two
perennial spring namely Anchlesar & Sardhro as well as temporary streams called
Bhatuyani River and ―Gordhro: River which flow during the rainy season. (ii) There are
some hilly tracks called ―Parker. The Granite Marble has been found there. ―Karoonjhar
Mountain‖ is near to Nagarparkar. (iii) There is no lake, Glacier, plains etc in the district.
(iv) Mostly this district is desert area. (v) Topography.
The Thar Region forms part of the bigger desert of the same name that sprawl over a vast
area of Pakistan & India from Cholistan to Nagarparkar in Pakistan and from the south of
the Haryana down to Rajistan in India.
This district is mostly deserted and consists of barren tract of the sand dunes covered
with thorny bushes. The ridges are irregular and roughly parallel that they often closed
shattered valleys which they raise to a height to some 46 meters. When there is rain these
valleys are moist enough admit cultivation and when not cultivated they yield luxuriant
crops of rank grass. But the extra ordinary salinity of the subsoil land consequent
shortage of portable water renders many tracks quite picturesque salt lakes which rarely a
day up.
The only hills a Nagarparkar, on the Northern edge of the Runn of Kutchh belongs to
quite a different geological series. It consist Granite rocks. Probably an outlying mass of
the crystalline rocks of the Arravelli range. The arravelli series belongs to Archean
system which constitutes the oldest rocks of the earth crust. This is a small area quite
different from the desert. The tack is flat a level expect close to Nagarparkar itself. The
principle range Karoonjhar is 19 Kms in length and attains a height of 305 m. smaller
hills rise in the east, which is covered with sars jungle and pasturage and gives rise to two
springs named Anchlesar & Sardhro as well as temporary streams called Bhatyani &
Gordhro after the rain.
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26. 3.4 GEOGRAPHY:-
Tharparkar district is located at the extreme South East corner of the province. It is one of
the poorest and under develop district in Sindh. It is flanked by Mirpurkhas and Umerkot
district, the most prosperous on its Northern side, on the west by Badin district, on the
East by Bharmar & Jaisalmer district of India and on the South of Runn of Kutchh.
District is approximately 250 kms across having in area of 19389 sq: Kms. The district is
divided into three ecological zones, the South Eastern is hilly rich in mineral deposits the
central area is Thar which sandy dunes and on the western side (very small portion) of
barrage area and fertile. During summer climate is hot and dry while winter is somewhat
mild. The rain fall varies from year to year. Most of the rain fall in moon soon period
between June & September and the winter rain are in significant.
3.5 LOCATION OF ACCESSIBILITY:-
North: Mirpurkhas & Umerkot Districts
East: Barmer & Jessalmer District of India
West: District Badin
South: Runn of Kuchh
95% of entire population depends on cultivation and cattle, while remaining in small
business. Like shopkeepers and manufacturing handmade carpets. The entire huge
area of this District is desert (expect small portion on 65636 Acres). There is only one
Crop in whole year in desert area, which also depends on rains. Rain is expected in
June, July and August when sowing season commences for maturity of crops, other 2-
3 rains are needed, else crops will dry and of no use consistently people of this area
confronting menace of drought almost after every one or two years. In event of no
rains, lends are barren. People and cattle face starving situation and start migration
with their cattle to other districts, to earn their lively hood.
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27. There are 3656933 cattle heads according to census of 1996, which no is biggest out of
all districts in Sindh. In event of sufficient rains this desert depicts classic, green and
beautiful look. Then everyone is happy. People from various places come over
particularly in Nagarparkar which place is worth to stay and live.
The socio-economic condition of this district solely depends on seasonal rain. The rain
are expected in the 2nd week of June up to 15th August, which are a lone beneficial for
sowing purpose. Further 2-3 more rains are require at some interval which are essentially
required for maturity of crops. But in absence of seasonal rains, the poverty is the fate of
the people of the area.
Mostly during heavy rains / floods, the barrage dehs and low lying areas specially ―Siran
Colony‖ Mithi are affected the people residing the low lying areas are shifted to safer
places, where Ration & Rescues and medical coverage is provided to them, till the rainy
season is over.
There is no possibility of flood as neither ‖River Indus‖ touches, nor big canal passes
through this district, only one ―Runn Distry‖ passes from barrage area of Taluka Mithi &
Diplo, for which irrigation authorities shall keep vigilance over the distry and inform the
administration about any mishap/ break of bund in case of heavy rain.
All the Officers / Officials of related Departments shall be appraised at the time of need
to take precautionary measures in advance and keep strict watch over the situation and
extend full cooperation with each other, irrigation Department and District
Administration so that there should be no case on any mishap.
3.6 THAR COAL FIELD:-
The Thar coalfield is located in Thar Desert, Tharparkar District of Sindh province in
Pakistan. The deposits - 6th largest coal reserves in the world were discovered in 1991 by
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28. Geological Survey of Pakistan (GSP) and the United State Agency for International
Development.
Pakistan has emerged as one of the leading countries - seventh in the list of top 20
countries of the world after the discovery of huge lignite coal resources in Sindh. The
economic coal deposits of Pakistan are restricted to Paleocene and Eocene rock
sequences. It is one of the world‘s largest lignite deposits discovered by GSP in 90‘s,
spread over more than 9,000 km2. Comprise around 175 billion tones sufficient to meet
the country‘s fuel requirements for centuries.
3.7 GENERAL GEOLOGY:-
The Thar coalfield area is covered by dune sand that extends to an average depth of over
80 meters and rests upon a structural platform in the eastern part of the desert. The
generalized stratigraphic sequence in the Thar coalfield area is shown in table. It
comprises Basement Complex, coal bearing Bara Formation, alluvial deposits and dune
sand.
The district is very rich in minerals resources like China Clay, Granite, Coal and Salt.
Thar coal field is spread over 9000 sqs KMs near Islamkot to Mithi it is one of largest
lignite (Coal) deposit in the world which constitute about 80% of coal deposited of
country. Coal deposited estimated 2000 Billion tons Government had intention to setup
power generating plat based on coal minerals at Tharparkar and Karachi. This project is
now inactive consideration of provincial as well as federal Government. Coal in
Tharparkar is discovered in the year 1991 during joint survey of Pakistan and other
countries. Coal deposits are in up to meet fuel requirement of the country for centuries as
open by experts.
Granite rock foundation is found in Nagarparkar region of Million tons Granite is
available at pockets spread over an area of 125 sq. KMs. It is beautiful and costly stone of
brownish colour. But due to no communication facilities it is taken in limited quantity.
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29. According to opinion of expert, China like Clay is found in Nagarparkar is comparable in
all respect to the imported one China like Clay deposit is estimated over 4 Million tons. A
part from this, salt mines are in Diplo Tehsil which has best deposits of raw salT
Water
The area is a part of the desert where precipitation is very little with a high rate of
evaporation. As such, limited water resources are of great significance.
A. Surface Water -The water is scanty and found in a few small ―tarais‖ and artificially
dug depressions where rain water collects. These depressions generally consist of silty
clay and caliche material.
B. Ground Water -The hydro geological studies and drill hole geology shows the
presence of three possible aquifer zones at varying depths: (i) above the coal zone (ii)
within the coal zone and (iii) below the coal zone.
Drilling data has indicated three aquifers (water-bearing Zones) at an average depth of 50
m, 120 m and more than 200 meters:
One aquifer above the coal zone: Ranges between 52.70 and 93.27 meters depth.
Second aquifer with the coal zone at 120 meters depth:
Varying thickness up to 68.74 meters.
Third aquifer below the coal zone at 200 meters depth:
Varying thickness up to 47 meters. Water quality is brackish to saline.
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31. Fig 3.2 A generalized subsurface stratigraphic succession is shown in the figure
3.8 GROUND WATER SOURCE:-
The past investigation drilling revealed that the coal is in-seams with extractable
thickness of 22 m at a depth of 110 m up to 200 m. The upper seams layer of coal reserve
also reportedly contains in-situ water. A recent, bankable feasibility study in the block 1
area has given the following information:
Groundwater is present in mainly three different horizons:
The base aquifer with pump tested transmissivities of 7.9x10-3 and 1.8x10-3 /s
is extending throughout the exploration area at a thickness of about 60 meter. This
Page | 31
32. aquifer has an extension in the Thar Desert of about 15,000 k . Recharge is
possibly from the Northeast beyond the Indian border.
The middle aquifer is composed of a variety of mainly disconnected sand lenses
and channel with partly high silt content and low permeability within the lignite
bearing Bara Formation and the sub recent formation. Recharge to these aquifer is
likely to be poor.
The Dune Sand Formation acts as a top aquifer with a water column of few
meters only at the formation base on top of the sub recent. Permeability here is in
the range of 10-5 m/s. Recharge of this aquifer is direct through rainfall
infiltration.
Groundwater qualities are saline in all aquifers with dominant sodium chloride contents.
TDS is around 7500 in the base aquifer of the exploration area and 4500 in the top
aquifer at the village of Varvai. The top aquifer at the village if Tilvai shows extreme
high values in the order of up to 11,000/14,000 TDS.
3.8.1 GROUND WATER REGIME THAR LIGNITE PROSPECT:-
There are three aquifer present in the Thar area as follows:
Top aquifer
It is located at the base of dune sand and stretches out all over the Thar Desert. In the
mining area, this aquifer shows a water column of up to 5 meter. The water table isabout
10 to 12m sea level. Permeability is around 3x10-7 m/s as show in below figure.
Intermediate Aquifer
This aquifer is scattered as lenses in sub-recent and Bara information. Permeability varies
between 10-5 to 10-7 m/s. Ground water in this aquifer is about 10-20m above sea level
as show in below figure,
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33. Bottom Aquifer
This aquifer is located beneath the coal formation down to the granite base. This is the
most dominant aquifer is terms of thickness, lateral extension and permeability. The top
of this aquifer starts some meters below the coal sequence: the grain size of the sand
varies from fine to coarse. Thickness of this aquifer in the mining area is around 50 –
60m that becomes larger in the West compared to that in the East as the granite basement
is submerging to the West. This aquifer is under high pressure and the pressure head is
around 25m above sea level. This aquifer is of special importance when opening the
mine, as it has to be depressurized in advance of reaching mining depth of about 100m,
otherwise, floor rupture would occur followed by flooding of the mine and collapse of the
high wall slopes. Therefore, it is necessary to know the horizontal extent of this aquifer
and the thickness as well as transmissibility. This aquifer covers an area of about 15,000
k . The aquifer is not homogenous with respect to permeability as show in below
figure,
3.9 INFRASTRUCTURE AT THAR COAL:-
Electricity
11 kV feeders emanating from Islamkot Gird Station to the Thar Coal Project with 200
Watts transformer and energized. 500 kv transmission lines. 500 kv transmission line has
been laid by WAPDA up to mining site.
Telephone
Fiber cable lying/installation of system between Mirpurkhas to Mithi exchanges
completed. 100 high guide tower (1‘‘ dia) is to be installed at Thar Coal site with DRS
equipment. Telephone facility is available up to Islamkot.
Water Supply
Water supply line from Mithi to Islamkot and Islamkot to coal mines Thar Halepoto) has
been completed and water reservoir of 6 lac gallons is available at (site (Block –ll). In
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34. addition, 2 reserve osmosis plant for desalination of water to provide potable water to
investors and local people has been installed at Sobharo Shah and Islamkot (near Thar
coalfield).
Construction of Airstrip
The scheme ―Construction of Airstrip at Islamkot‖ costing Rs. 120 million is under
implementation
Railway Line
Pakistan Railway conducted feasibility study of railway line at Thar coal field to facilitate
transportation of coal equipment the railway route has been approved by Chief Minister
of Sindh.
Town Planning of Islamkot
Town planning of Islamkot nearest town to coal field has also been sponsored for
rehabilitation/resettlement of the village located with coal field vicinity displaced
population will be relocated by providing them all necessary facilities in the nearest
township.
Thar Lodge
The scheme for the construction of 20-bedded accommodation to facilitate foreign and
local investors at Islamkot has been approved at estimated cost of Rs. 40978 million,
construction is in process.
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35. CHAPTER NO.4
INTRODUCTION TO SURPAC FOR ORE BODY MODELING
4.1 INTRODUTION TO SURPAC:-
Surpac is the world‘s most popular geology and mine planning software, supporting open
pit and underground operations and exploration projects in more than 110 countries. The
software delivers efficiency and accuracy through ease-of-use, powerful 3D graphics and
work flow automation that can be aligned to company-specific processes and data flows.
Surpac addresses all the requirements of geologists, surveyors, and mining engineers in
the resource sector and is flexible enough to be suitable for every commodity, ore body
and mining method. Its multilingual capabilities allow global companies to support a
common solution across their operations.
4.1.1 SURPAC BENEFIT:-
Comprehensive tools include: drill hole data management, geological modeling,
block modeling, geostatistic, mine design, mine planning, resource estimation,
and more.
Increased efficiencies within teams result from better sharing of data, skills and
project knowledge.
All tasks in Surpac can be automated and aligned to company-specific processes
and data flows.
Software ease-of-use ensure staffs develop an understanding of the system and of
project data quickly.
Surpac is modular and easily customized.
Surpac reduces data duplication by connecting to relational database and
interfacing with common file formats from GIS, CAD and other systems.
Integrated production scheduling with Gemcom Mine Schedule™.
Multilingual support: English, Chinese, Russian, Spanish, German and French.
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36. 4.2 GEOLOGICAL DATABASE:-
No prior knowledge of the geology database module is required: however a good
understanding of the Surpac Vision Core modules is required. A recommended
prerequisite is the principles of Surpac Vision tutorial. A basic understanding of drill
holes, sampling and database principles is needed. Topics that will be covered include:
Database Structure
Creating New Tables
Viewing Data in the Graphics Environment
Extracting Data
Polygonal Resource Calculation
Creating a Database
Reporting
Figure 4.1 showing drilholes accroding to geological table
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37. Figure 4.2 showing closed view of drillhole (pink color showing Lignite)
4.3 STRING FILES:-
The most common file format used for storing information in Surpac is a string file. A
stringFile contains coordinate information for one or more points, as well as optional
descriptive Information for each point: It is important to understand how Surpac
organizes and usesData.
Stored within a string file: this will enable you to work more efficiency with strings.
String Data Hierarchy:-
Data in a string file is classified:-
Points.
Segments.
Strings.
All points in a string file are grouped into segments, which are further grouped into
strings.
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38. String File
String 1 String 2 String99
Segment 1 Segment 1 Segment 1
Point 1 Point 6 Point 14
Point 2 Point7 Point 15
Point 3 Point8 Point 16
Point 4 Point 9
Point 10
Segment 2
Point 11
Point 17
Point 12
Point 13
Segment 3
Point 5
Point 18
Point 19
Figure 4.3 string data hierarch chart
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39. 4.3.1 TYPES OF STRINGS:-
There are three types of strings:-
Open.
Closed.
Spot Height.
The table below explains these terms.
Surpac term Common term Example
Open string Line Drill hole trace
Closed string Polygon Property boundary
Spot height string Points not associated with Blast hole collar
a line or polygon locations
4.4 DIGITAL TERRAIN MODEL (DTM):-
Surpac Modeling allows us to use triangulation to create two-dimensional models known
as Digital Terrain Models (DTMs). This document introduces the theory behind surface
modeling processes and provides detailed examples using the surface modeling functions
in Surpac Vision. By working through this manual you will gain skills in the
construction, use of and modification of DTMs.
4.4.1 SURPACE MODELING CONCEPTS:-
A digital terrain model (DTM) is made up of a surface joining adjacent strings. It is
formed as a combination of those string lines, and of joining points on string.
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40. FIG: 4.4.1 A set of strings
The joining process continues until the surface consists only of non-overlapping triangles.
The software choose the joins to produce the best –conditioned triangle – i.e. Those
closest to equilateral triangles.
FIG: 4.4.2becomes a surface when joined by lines
The resulting DTM can be thought of as an undulating patchwork quilt made up of
triangular patches.
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41. FIG: 4.4.3 Digital terrain model (DTM)
A Digital Terrain Model (DTM) is how Surpac model surfaces. Surfaces are used in
Surpac for such things as 3D visualization and for calculating volumes. Almost any
superficial feature can be modeled as a DTM, including natural topography, litho logical
contacts, bedrock/overburden contact, or water tables.
DTMs must come from string data. String files contain the raw data, whereas DTM files
contain a mapping of trios of points in the string file that constitute a triangle. DTMs are
made of triangles, with each point of each triangle matched to a point in the original
string file. Consequently DTM file are not valid without the original string file. That is, a
DTM file cannot be opened if the original string file of the same name is not accessible.
Another rule for the construction of DTMs is that DTMs cannot fold back on themselves.
That is, a DTM cannot have multiple Z values for a given X, Y coordinate. Therefore you
cannot model overhanging or vertical surfaces.
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42. FIG: 4.5 DIGITAL TERRAIN MODEL (DTM)
If the surfaces are to be used for further processing, such as for calculating volumes or
higher end functionality within the surface menu, then the object must be named object 1
translation 1.It is important to consider this when creating the surface, as each surface
must then be places in a separate file.
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43. CHAPTER NO.5
ORE BODY MODELING BY USING SURPAC
5.1 GEOLOGICAL DATABASE:-
In order to understand the geological database, we collected almost all the prospecting
data of the mine, and chose the main elements, including coal, as the territorial variables.
Then, we used the surpac version 6.2 and the collected data to establish the mine‘s
geologic database .geologic data base is the foundation of the 3D modeling. It is
necessary for building 3D model of ore body, analyzing the bore hole data, estimating
and calculating coal reserves. The geologic database has powerful post-processing
functions, which can be used to edit, inquire, update analyze and display the data
visually. Fig: 5.1 show the 3D displaying o0f the spatial location of the boreholes.
The geological database module in surpac is one of the most important set of tools we
use. the geological data base in our project consists of three tables, each of which
contains different kind of data. Each table contains number of fields. Each table will also
have many records, with each record containing the data fields. surpac uses a relational
database model and supports several different types of data bases , including oracle,
paradox and Microsoft access. Surpac also supports open data base connectivity (ODBC)
and can connect to database across networks. A database can contain up to 50 tables and
each table can have a maximum of 60 fields. Surpac requires two mandatory tables
within a database: collar and survey.
Drill hole data is the starting points of All mining projects and constitutes the basis on
which feasibility studies and ore reserve estimation are done. We use the drill hole data of
thar coal project block –IV which is done by RWE (German company). Geological
database consists of following tables.
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44. Collar table
Surveys table
Geology table
5.1.1 COLLAR DATA:-
The information stored in the collar table describes the location of the drill hole collar,
the maximum depth of the hole and whether linear or carvel hole trace is to be calculated
when retrieving the hole. Optional collar data may also be stored for each drill hole. For
example, date drilled type of drill hole or project name. The fields in collar table are
shown below.
Fields Description
Hole id Id no of drilled hole
Y Northing
X Easting
Z Level
COLLAR Max: depth Max depth of hole
TABLE Hole path Angle of drilled hole
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45. hole id y x z max depth hole path
RE-01 775058 369520.1 62.2 215.1 LINEAR
RE-02 773092.9 371409.8 57.5 213.84 LINEAR
RE-03 772221.1 369893.3 55 212.09 LINEAR
RE-04 772251.9 367480.8 54.4 226.03 LINEAR
RE-05 774080.2 370315.2 76.2 211 LINEAR
RE-06 772370.8 368525.8 68.2 221.2 LINEAR
RE-07 772024.7 370979.2 57.7 209.6 LINEAR
RE-08 773655.6 367658 59.7 205.74 LINEAR
RE-09 770861 369340 51.5 203.4 LINEAR
RE-10 775098 368740 61.9 200 LINEAR
RE-11 772458 366453 51.2 215.2 LINEAR
RE-12 774252.5 369604.8 64.1 227.3 LINEAR
RE-13 773302 366435 52.4 209 LINEAR
RE-14 774566 368697 58.8 200.1 LINEAR
RE-15 775375 367891 60.7 218.2 LINEAR
RE-16 774300 366918 55.8 211.2 LINEAR
RE-17 775029 366975 63.4 220.9 LINEAR
RE-18 773302 366435 52.4 215.1 LINEAR
RE-19 775014 369500 52.3 223.9 LINEAR
RE-20 772458 366453 51.2 236.2 LINEAR
RE-21 772421.2 366352 54.23 215.4 LINEAR
RE-22 771597 370296.6 55.3 272.9 LINEAR
RE-23 772302 373145 55.2 222.7 LINEAR
RE-24 772419.1 370255.4 53.8 218.7 LINEAR
RE-25 773055 370233 54 215.1 LINEAR
RE-26 772615.2 373131.6 72.9 228.9 LINEAR
RE-27 771621.1 374336.2 57.7 214.88 LINEAR
RE-28 774855.9 370080.8 71.8 228.6 LINEAR
RE-29 773738.8 368266 56.9 212.02 LINEAR
RE-30 773119.9 368902.3 58.1 228.75 LINEAR
Table 5.1 collar data of drilled bore hole
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46. 5.1.2 SURVEY DATA:-
The survey table stores the drill hole survey information used to calculate the drill hole
trace coordinates. mandatory fields include : down hole survey depth , dip and the
azimuth of the hole .for a vertical hole which has not been surveyed , the depth would be
the same as the max depth field in the collar table , the dip would be -90 and the azimuth
would be zero . The y, x and z fields are used to store the calculated coordinates of each
survey. Optional fields for this table may include other information taken at the survey
point e.g. core orientation.
Fields Description
Hole ID ID number of drilled hole
Path Linear
Y Northing
X Easting
Z Level
Max depth Maximum depth of hole
Survey
Hole path Angle of drilled hole
Dip
Azimuth
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47. Hole id M ax de pth Dip Azimuth
RE-01 215.1 -90 0
RE-02 213.84 -90 0
RE-03 212.09 -90 0
RE-04 226.03 -90 0
RE-05 211 -90 0
RE-06 221.2 -90 0
RE-07 209.6 -90 0
RE-08 205.74 -90 0
RE-09 203.4 -90 0
RE-10 200 -90 0
RE-11 227.3 -90 0
RE-12 227.3 -90 0
RE-13 -90 0
RE-14 200.1 -90 0
RE-15 218.2 -90 0
RE-16 211.2 -90 0
RE-17 220.9 -90 0
RE-18 215.1 -90 0
RE-19 223.9 -90 0
RE-20 236.2 -90 0
RE-21 215.4 -90 0
RE-22 272.9 -90 0
RE-23 222.7 -90 0
RE-24 218.7 -90 0
RE-25 215.1 -90 0
RE-26 228.9 -90 0
RE-27 214.88 -90 0
RE-28 228.6 -90 0
RE-29 212.01 -90 0
RE-30 228.75 -90 0
Table 5.2 survey table
5.1.3 GEOLOGICAL GEOLOGY DATA:-
It is interval tables require the depth at the start of the interval and the depth at the end of
the interval, called the depth from and depth to fields respectively. The fields are in this
table are as follows.
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48. Fields Description
Hole id Id no of drilled hole
Depth from Depth from
Geology Depth to Depth to
Rock code Litho logical code
Table 5.3 showing geological data
HOLE ID DEPTH FROM DEPTH TO ROCK CODE THICKNESS
RE-01 0 81 DUNE SAND 81
RE-01` 81 101 SILTSTONE 20
RE-01 101 102 SAND CL 1
RE-01 102 124 SILTSTONE 22
RE-01 124 127 SAND CL 3
RE-01 127 131.27 SILTSTONE 4.27
RE-01 131.27 131.52 SANDSTONE 0.25
RE-01 131.52 132.76 SILTSTONE 1.24
RE-01 132.76 135.36 CLAY STONE 2.6
RE-01 135.36 135.81 SILTSTONE 0.45
RE-01 135.81 138.86 SANDSTONE 3.05
RE-01 138.86 139.56 CLAY STONE 0.7
RE-01 139.56 147.55 SAND CL 7.99
RE-01 147.55 148.7 LIGNITE 1.15
RE-01 148.7 150.15 CLAY STONE 1.45
RE-01 150.15 150.9 LIGNITE 0.75
RE-01 150.9 151.7 CLAY STONE 0.8
RE-01 151.7 154.55 LIGNITE 2.85
RE-01 154.55 160.45 CLAY STONE 5.9
RE-01 160.45 161.4 LIGNITE 0.95
RE-01 161.4 165.29 CLAY STONE 3.89
RE-01 165.29 165.59 LIGNITE 0.3
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