MINE SURVEYING INTRODUCTION TO THE IMPORTANCE OF MINE SURVEYING Mine survey is part of mining science and technology that deals with measurement on the surface and in the earth crust, during exploration, exploitation of minerals and construction of mining plants. It includes all measurements, calculations and mapping which serve the purpose of ascertaining and documenting information at all stages from prospecting to exploitation and utilizing mineral deposits both by surface and underground working. The results of mine surveys are then used for the plotting of plans conditions of deposits and also for the solution of various problems of the mining geometry. The principal tasks of mine- surveying include; (1)The interpretation of the geology of mineral deposits in relation to the economic exploitation thereof(2)The investigation and negotiation of mineral mining rights (3)Making and recording, and calculations of mine surveying measurements (4)Mining cartography (5)Investigation and prediction of effects of mine working on the surface and underground strata (6)Mine planning in the context of local environme nt and subsequent rehabilitat ion (7)The location, structure, configuration, dimensions and characteristics of the mineral deposits and of the adjoining rocks and overlying strata. The assessment of mineral reserves and the economics of their exploitation. Other mine surveying activities include: a)The acquisition, sale, lease and management of mineral properties. b)Providing the basis of the planning, direction and control of mine workings to ensure economical and safe mining operations.
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Mine survey is part of mining science and technology that deals with measurement on the
surface and in the earth crust, during exploration, exploitation of minerals andconstruction of mining plants. It includes all measurements, calculations and mapping
which serve the purpose of ascertaining and documenting information at all stages from
prospecting to exploitation and utilizing mineral deposits both by surface and
underground working. The results of mine surveys are then used for the plotting of plans
conditions of deposits and also for the solution of various problems of the mining
geometry.
The principal tasks of mine- surveying include;
(1) The interpretation of the geology of mineral deposits in relation to the economic
exploitation thereof
(2) The investigation and negotiation of mineral mining rights
(3) Making and recording, and calculations of mine surveying measurements
(4) Mining cartography
(5)
Investigation and prediction of effects of mine working on the surface andunderground strata
(6) Mine planning in the context of local environment and subsequent rehabilitation
(7) The location, structure, configuration, dimensions and characteristics of the
mineral deposits and of the adjoining rocks and overlying strata. The assessment
of mineral reserves and the economics of their exploitation.
Other mine surveying activities include:
a) The acquisition, sale, lease and management of mineral properties.
b) Providing the basis of the planning, direction and control of mine workings to ensure
c) The study of rock and ground movements caused by mining operations, their
prediction, and the precautions and remedial treatment of subsidence damage.
d) Assisting in planning and rehabilitation of land affected by mineral operations and
collaborating with local government planning authorities.
Nevertheless, mine surveyors have to participate in all stages of the operation of mining
plants from the exploration of a mineral deposit and up to the abandonment of a mine
after it has been worked out, and to perform specific survey work at all these stages;
(a) Exploration of mineral deposits: the mine surveyor make land surveys, the determine
and transfers into nature the positions of exploring workings (pits , ditches etc) makes
the surveys of exploring workings assaying points, seams outcrops, bedding elementsof mineral deposits and enclosing rock, and complies the graphical documentation
representing the shape and bedding conditions of a deposit. Mine-surveying plans and
sections plotted by the results of geological prospecting are used for the calculations
of mineral reserve and design of mining plant.
(b) Design and construction of mining plant the mine surveyor participates in
construction surveying; the determination of the boundaries of mine field according
to the current regulations on land allotment; design of working systems and surface
structures; development of measures for the protection of surface and underground
structures against harmful influence of underground working; compilation of the
graphs of work organization and plans of mining work for the periods of construction
and exploitation of a mining plant; and the calculation of the losses and industrial
reserves of minerals.
(c) Exploitation of deposits: the role of the mine surveyor at the stage of exploitation is
extremely important and includes the following operation; surveying of workings;
assigning of directions to working; compilation of plans by the results of surveys;
control of the mining work in accordance with the design specifications and safety
regulations; reclamation of land planning of the preparatory and stopping mining
work, calculation of the balance and industrial reserves, losses and dilution of
minerals.
The Mine Surveyor is one of the key contributors to the welfare of the mining industry.
They are responsible for maintaining an accurate plan of the mine as a whole and will
update maps of the surface layout to account for new buildings and other structures, as
well as surveying the underground mine workings in order to keep a record of the mining
operation.
More importantly, the surveyor is involved in the measuring process to calculate ore
production, in volume or mass units, from the mining operation. In addition to calculation
of ore production from the mining operation, the volume of the dumps of waste
accumulating on the surface of the mining property will also be surveyed. This aspect of
the work has turned the mine surveyor into a manager of the µresources¶ of the mine.
SURVEYING TOOLS
PLANS
These are drawings of orthogonal projections of objects onto a horizontal plane. They are
widely used for the representation of the Earth¶s surface and mining workings. Survey
plans usually contain the elevation marks (height coordinates) of particular points or are
constructed in isohypses; in the latter case, they are essentially projections with numerical
data.
MAPS:
These are representations of a geographic area, usually a portion of the earth's surface,drawn or printed on a flat surface. In most instances a map is a diagrammatic rather than
a pictorial representation of the terrain; it usually contains a number of generally accepted
symbols, which indicate the various natural, artificial, or cultural, features of the area it
covers. The basic type of map used to represent land areas is the topographic map. Such
maps show the natural features of the area covered as well as certain artificial features,
known as cultural features. Political boundaries, such as the limits of towns, countries,
and states, are also shown. Because of the great variety of information included on them,
topographic maps are most often used as general reference maps. A topographic map is atype of map characterized by large-scale detail and quantitative representation of relief,
usually using contour lines in modern mapping, but historically using a variety of
methods. Traditional definitions require a topographic map to show both natural and
man-made features. A topographic map is typically published as a map series, made up of
two or more map sheets that combine to form the whole map. A contour line is a
combination of two line segments that connect but do not intersect; these represent
elevation on a topographic map.
Basic elements of a map
Geographic Grid: In order to locate a feature on a map or to describe the extent of an
area, it is necessary to refer to the map's geographic grid. This grid is made up of
meridians of longitude and parallels of latitude. By agreed convention, longitude is
marked 180° east and 180° west from 0° at Greenwich, England. Latitude is marked 90°
north and 90° south from the 0° parallel of the equator. Points on a map can be accurately
defined by giving degrees, minutes, and seconds for both latitude and longitude. Maps are
usually arranged so that true north is at the top of the sheet, and are provided with a
compass rose or some other indication of magnetic variation.
Scale: The scale to which a map is drawn represents the ratio of the distance between two
points on the earth and the distance between the two corresponding points on the map.
The scale is commonly represented in figures, as 1:100,000, which means that one unit
measured on the map (say 1 cm) represents 100,000 of the same units on the earth's
surface.
Objects are depicted in mine-surveying plans by diminishing the results of natural
measurements. The degree of diminution of a line in a plan is determined by the scale i.e
a dimension less fractional number in which the numerator is unity and the denominator
A system of coordinate is essential for all permanent mining operations. It is very
desirable that all mining operations in a given area be tied into the same system, as this
minimizes problems of boundaries and connections. Wherever possible, this systemshould be tied into and made part of the state or regional grid system. It is desirable to
orient the coordinate grid on a true north line and to position the origin of the coordinates
so that all of the work will be in the north-east quadrant, making the north and east
coordinates always positive. This can be done by subtracting suitable constant values
from the north and east coordinates of the regional system. The residual values are of
more convenient magnitude and can be used as the local mine coordinates. If the long
axis of the mineralization is not generally north-south or east-west, it may be useful to
establish a secondary coordinate system oriented parallel to the long axis. This makes it
possible to depict the mine workings more conveniently on the working maps.
Commonly the elevations will be based on sea level, as taken from established stations. If
this is not the case, a different reference elevation may be necessary. Frequently, this is
chosen so as to be above any possible one working, making all elevations have a negative
sign. This can be ignored if the measurements are considered to be µdown¶ from the plane
instead of µup¶.
Most mining operations are concentrated within relatively small surface areas. Thus it is
possible to ignore most of the problems introduced by the curvature of the earth and by
the convergence of the meridians except in the most precise work. A level surface is
considered to be parallel and perpendicular to the lines of latitude. These simplifying
assumptions are entirely satisfactory for compact mining operations but may not be
adequate for distances exceedingly several kilometers. In such cases the principle of
A contour line (also isoclines or isarithm) of a function of two variables is a curve along
which the function has a constant value. In cartography, a contour line (often just called a
"contour") joins points of equal elevation (height) above a given level, such as mean sea
level. A contour map is a map illustrated with contour lines, for example a topographic
map, which thus shows valleys and hills, and the steepness of slopes. The contour
interval of a contour map is the difference in elevation between successive contour lines.
More generally, a contour line for a function of two variables is a curve connecting points
where the function has the same particular value. The gradient of the function is always
perpendicular to the contour lines. When the lines are close together the magnitude of the
gradient is large: the variation is steep. A level set is a generalization of a contour line for
functions of any number of variables.
Contour lines are curved or straight lines on a map describing the intersection of a real or
hypothetical surface with one or more horizontal planes. The configuration of these
contours allows map readers to infer relative gradient of a parameter and estimate that
parameter at specific places. Contour lines may be either traced on a visible three-
dimensional model of the surface, as when a photogrammetrist viewing a stereo-model plots elevation contours, or interpolated from estimated surface elevations, as when a
computer program threads contours through a network of observation points of area
centroids. In the latter case, the method of interpolation affects the reliability of
individual isoclines and their portrayal of slope, pits and peaks.
CARTOGRAPHY
Cartography is the study and practice of making maps. Combining science, aesthetics,
and technique, cartography builds on the premise that reality can be modeled in ways that
communicate spatial information effectively.
The fundamental problems of traditional cartography include:
critical angle of vision 60´ and the distance of best vision to an object 250mm, the
resolution is equal to 0.073mm or roughly 0.1mm).
PLANIMETER AND AREAS
A planimeter is a measuring instrument used to determine the area of an arbitrary two-
dimensional shape. They consist of a linkage with a pointer on one end, used to trace
around the boundary of the shape. The other end of the linkage is fixed for a polar
planimeter and restricted to a line for a linear planimeter. Tracing around the perimeter of
a surface induces a movement in another part of the instrument and a reading of this is
used to establish the area of the shape. The planimeter contains a measuring wheel that
rolls along the drawing as the operator traces the contour. When the planimeter's
measuring wheel moves perpendicular to its axis, it rolls, and this movement is recorded.
When the measuring wheel moves parallel to its axis, the wheel skids without rolling, so
this movement is ignored. That means the planimeter measures the distance that it¶s
measuring wheel travels, projected perpendicularly to the measuring wheel's axis of
rotation. The area of the shape is proportional to the number of turns through which the
measuring wheel rotates when the planimeter is traced along the complete perimeter of the shape. Developments of the planimeter can establish the position of the first moment
of area (center of mass), and even the second moment of area.
The pictures show a linear and a polar planimeter. The pointer M at one end of the
planimeter follows the contour C of the surface S to be measured. For the linear
planimeter the movement of the "elbow" E is restricted to the y-axis. For the polar
planimeter the "elbow" is connected to an arm with fixed other endpoint O. Connected to
the arm ME is the measuring wheel with its axis of rotation parallel to ME. A movement
of the arm ME can be decomposed into a movement perpendicular to ME, causing the
wheel to rotate, and a movement parallel to ME, causing the wheel to skid, with no
shapes. These other surfaces can be mapped as well. Therefore, more generally, a map
projection is any method of "flattening" into a plane a continuous surface having
curvature in all three spatial dimensions.
Projection as used here is not limited to perspective projections, such as those resulting
from casting a shadow on a screen, or the rectilinear image produced by a pinhole camera
on a flat film plate. Rather, any mathematical function transforming coordinates from the
curved surface to the plane is a projection.
Carl Friedrich Gauss's Theorema Egregium proved that a sphere cannot be represented on
a plane without distortion. Since any method of representing a sphere's surface on a plane
is a map projection, all map projections distort. Every distinct map projection distorts in a
distinct way. The study of map projections is the characterization of these distortions.
A map of the Earth is a representation of a curved surface on a plane. Therefore a map
projection must have been used to create the map, and, conversely, maps could not exist
without map projections. Maps can be more useful than globes in many situations: they
are more compact and easier to store; they readily accommodate an enormous range of
scales; they are viewed easily on computer displays; they can facilitate measuring
properties of the terrain being mapped; they can show larger portions of the Earth'ssurface at once; and they are cheaper to produce and transport. These useful traits of
maps motivate the development of map projections.
Many properties can be measured on the Earth's surface independently of its geography.
Some of these properties are: Area, Shape, Direction, Bearing, Distance and Scale.
Map projections can be constructed to preserve one or more of these properties, though
not all of them simultaneously. Each projection preserves or compromises or
approximates basic metric properties in different ways. The purpose of the map
determines which projection should form the base for the map. Because many purposes
exist for maps, many projections have been created to suit those purposes.
Another major concern that drives the choice of a projection is the compatibility of data
sets. Data sets are geographic information. As such, their collection depends on the
chosen model of the Earth. Different models assign slightly different coordinates to the
same location, so it is important that the model be known and that the chosen projection
be compatible with that model. On small areas (large scale) data compatibility issues are
more important since metric distortions are minimal at this level. In very large areas(small scale), on the other hand, distortion is a more important factor to consider.
Construction of a map projection
The creation of a map projection involves two steps:
i. Selection of a model for the shape of the Earth or planetary body (usually choosing
between a sphere or ellipsoid). Because the Earth's actual shape is irregular,
information is lost in this step.
ii. Transformation of geographic coordinates (longitude and latitude) to Cartesian (x,y)
or polar plane coordinates. Cartesian coordinates normally have a simple relation to
eastings and northings defined on a grid superimposed on the projection.
Some of the simplest map projections are literally projections, as obtained by
placing a light source at some definite point relative to the globe and projecting its
features onto a specified surface. This is not the case for most projections which are
defined only in terms of mathematical formulae that have no direct physicalinterpretation.
ROLE OF MINE SURVEYING SERVICE IN MINING SAFETY
Modern mining can be characterized by ever increasing depths of mines and accordingly,
more complicated geological and hydrological conditions. With an increase in the mining
depth, rock pressure increases intensively. moreover the cases of sudden rock, coal, gas
and water outbursts, self ignition of coal, etc. are more probable to occur in deeply
bedded seams. Under such conditions, special methods and means are required for
carrying out the stoping and preparatory mining operations, which should be strictly
observed and controlled properly to ensure the safety and efficiency of mining.
Under the conditions of elevated hazard of mining, mine surveying service plays an
important part and has certain specifics. In many aspects of mining safety, mine
surveying service takes the prime role and is responsible for making decisions which are
obligatory for all other mining specialists and workers. To ensure safety control, minesurveyors determine the boundaries of harzardous zones and represent them on the plans
of the mining workings are approaching harzardous zones, participate in the development
of safety measures, and observe that these measures fulfilled properly. There are three
principal groups of hazardous zones which may be associated with:
a) Flooded mining workings;
b) Formation of zones of elevated rock pressure between adjacent seams, and
c) Formation of unprotected zones and zones of elevated rock pressure in seams liable to
outbursts.
Hazardous zones associated with flooded workings can in turn be divided into the
following types:
a) Zones near flooded or gassy workings in a single seam
b) Those near flooded or gassy workings in adjacent seams;
c) Zones near flooded workings driven in the overburden;
d) Those near unplugged or poorly plugged boreholes; and
e) Zones near tectonic disturbances (dislocations)
In mine surveying practice, dangerous conditions are encountered most often in workings
approaching flooded or gassy old workings. Methods for the construction of safe
boundaries and special safety measures of the mining work have been developed for each
the earth. In underground mining, vertical surveys are carried out in order to determine
the height marks of individual points established in underground workings, to assign the
specified slope (grade) to workings, to plot longitudinal and vertical profiles and sections,
to determine the height of marks of the characteristic points of deposits (seams); thesemeasurements are essential for the solution of mining geometry and mine geometrization
problems.
If a whole series of heights is given relative to a plane, this plane is called a datum; and in
topographical work; the datum used is the mean level of the sea, since it makes
international comparism of heights possible. This level is termed ordinance datum and is
the one which will normally be used, though on small works, an ordinary datum may be
chosen.
The basic equipment required in leveling is:
a) A device which gives a truly horizontal line (the level),
b) A suitable graduated staff for reading vertical heights (the leveling staff),
c) In addition, equipment is necessary to enable the points leveled to be located
relative to each other on a map plan or section, this might be for example chain
tape, tacheometer or plane table etc.
Procedure in leveling:
The basic operation is the determination of the difference in level between two points.
If the readings on A and B are 3.222m and 1.414m respectively, then the diffence in level
between A and B is equal to AC i.e 3.222-1.414=1.808m and this represent a rise in the
height of the land at B relative to A. if the readings at B is greater than at A, say 3.484m,
then the difference in level would be 3.484-3.222=0.262m, and this would represent a fallin the height of the land at B relative to A. thus we have that in any two successive staff
readings:
If 2nd reading is less than 1st, then it represents a rise, If 2nd reading is greater than the 1st ,
, then it represent a fall.
If the actual level of one of the two points is known, the level of the other may be found
by either adding the rise or subtracting the fall. The levels at A and B are known as
reduced levels (R.L) as they give the level of the land at these points reduced or referred
to a datum level (in case ordinance datum, which the mean height of Newline) and this
method of reducing the staff reading gives a system of booking known as the Rise and
Fall method.
A second method is known as the height of collimation method, also exists and since the
two methods are in common use they must both be known. In the second method, the
height of the line of collimation above the datum is found by adding the staff reading
obtained with the staff on a point of known level to the R.L of that point.
Thus, in 3.22 the height of collimation is 128.480+3.222=137.702m AOD and this will
remain constant until the level is moved to another position. The levels of points such as
B are determined by deducting the staff reading at these points from the height of
collimation.
a) Level at B= height of coll. Reading at B
= 131.702-1.414=130.288m AOD
b) Level at B = height of collimation Reading at B
This could be dealt with by means of an example and we will consider the line of levels
down the centre line of the road as shown in the plan below:
The instrument is set up at a convenient position p such that a bench mark (B.M) may be
observed. Bench marks are points of known elevation above ordinance datum which have
been established by surveyors of the of the ordinance survey. The commonest types are in
the form of a broad arrow on permanent features such as bridge, parapets etc.
The 1st reading made with the staff on a point of known reduced level (which need not, of
course be a bench mark) is known as a backsight (B.S), and this term will now be used to
denote that reading taken immeadiately after setting up the instrument with the staff on a
point of known level. The staff is now held at a point A, B and C in turn and readings
which are known as intermediate sights are taken. It is found that no readings after D are possible due to either change is in level of the ground surface or some obstruction to the
line of sight and it Is therefore necessary change the position off the instrument. The last
reading on D is then known as foresight (F.S) and is final taken before moving the
instrument. The point D is itself is known as change point because it is the staff position
of the level is being changed.
The instrument is moved to Q setup and leveled and the reading a backsight, taken on the
staff at the change point D followed by intermediate sights (I.S) with the staff on points atwhich levels are required until a further change becomes necessary resulting in a
(all R.L¶s except the first) = (each instrument height) × (number of intersights and
F.S¶s deduced from it) - (F.S + I.S)
Reduction is easier with the height of collimation method when leveling for earthworks
and karge numbers of intermediate sights are taken from each position of the instrument.
The Gyro-Theodolite
A gyro-theodolite is a surveying instrument composed of a gyroscope mounted to a
theodolite. It is used to determine the orientation of true north by locating the meridian
direction. It is the main instrument for orientating in mine surveying and in tunnel
engineering, where astronomical star sights are not visible.
The gyro-theodolite in its present form is a recently developed instrument which
revolutionizes the task of carrying azimuth into underground mines. It is lightweight, self
contained apparatus giving results of great accuracy in a short time. It does not require
the use of a shaft, nor does it interfere with normal mine operations if there is an unused
heading of sufficient length to a back sight line. It is operated by one instrument man and
a recorder. Similar units are supplied by several manufacturers.
The basic unit consists of a very precise gyroscope suspended by a short thin metallic band. The gyro is housed in a metal case which mounts on top of a theodolite. A
gyroscope is mounted in a sphere, lined with Mu-metal to reduce magnetic influence,
connected by a spindle to the vertical axis of the theodolite. The battery-powered gyro
wheel is rotated at 20,000 rpm or more, until it acts as a north-seeking gyroscope. A
separate optical system within the attachment permits the operator to rotate the theodolite
and thereby bring a zero mark on the attachment into coincidence with the gyroscope spin
axis. Power is supplied by a portable battery which activates a converter supplying
alternate current to the gyro meter. The position of the gyro is observed through an
illuminated eyepiece. The gyro is clamped in position while being moved and brought up
to speed. When the rapidly revolving gyro is uncase its axis horizontal and pointed
toward some particular spot on the tripod stands, however, is revolving. This with gravity
leveling would have to be run over a long distance. Surveyors use absolute locations
gotten through GPS instruments to make maps and determine property boundaries.
GPS, or Global Positioning Systems, are used extensively by surveyors as they provide
accurate latitude and longitude positions. GPS systems use radio signals from navigationsatellites to determine the position. Two types of GPS instruments exist; all-in-one
receivers, which have the GPS receiver, antenna and data collector built into the same
device, and standalone receivers consisting only of the GPS receiver and antenna.
Standalone receivers need to be connected to computers to access the data.
Trimble GeoXH: The Trimble GeoXH is a handheld all-in-one GPS Geographic
Information System. device. This GPS instrument is often used for electric and gas
utilities, land reform projects, water and wastewater services where on-the-spot
positioning is very important. The GeoXH features an internal antenna, but an external
antenna can be attached to the device to achieve decimeter accuracy. With 128 MB
RAM, 1GB storage space and a 530 MHz processor, the device supports working with
maps and large data sets in the field. Industry standard Windows Mobile 6 operating
system powers this handheld device. Bluetooth and LAN network connection is possible
with the GeoXH to transfer data to and from other devices.
MobileMapper CX: The MobileMapper CX is another all-in-one handheld GPS receiver
for universal Geographic Information System collection. This device provides real-time
sub-meter and sub-foot accuracy and supports Bluetooth wireless technologies as well as
DGPS networking. The device supports SD storage cards, which are used in digital
cameras today, and works with a replaceable battery. Surveyors use the MobileMapper
CX to create or update maps for analysis and storage.
GMS-2 Pro: This handheld dual constellation tracking GPS receiver consists of an
integrated laser distance meter, digital camera, bar code reader and digital compass.
Surveyors can take digital photographs of structures and upload them directly to their
Geographic Information System. Each photograph can be geo-tagged with the GPScoordinates. An internal laser distance meter, compass and tilt sensor work together to
map offset points. The GMS-2 Pro supports Bluetooth and other network connections, as
well as USB data transfer.
GPS Pathfinder ProXH: The GPS Pathfinder ProXH features a GPS receiver, antenna and
battery. It is a standalone device, which connects to a field computer via a Bluetooth
wireless connection. The GPS Pathfinder ProXH can be connected to computers, laptops,
tablet PCs and PDAs. The device delivers sub-foot accuracy, which can be enhanced by