mine surveying compile

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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 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

economical and safe mining operations.



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



shows how many time a line depicted in the plan can be laid off along the corresponding

horizontal distance in the terrain. This is what is called the numerical scale is what is

called the numerical scale of length, or simply numerical scale.

Consequently, S = 1/M where M is the denominator of the numerical scale.

In plans, numerical scales are written as simple fractions, for example;

1/500,1/1000.1/2000,1/10,000 etc.

The larger the denominator, the smaller the scale. For instance, if the horizontal

distance of a line on the terrain is equal to 174.30m and the scale of plan is 1/2000, the

length of the corresponding line on the plan will be 174.3:20= 8.71 cm; if a line on a

plan made on a scale 1/5000 is equal to 10.2cm the horizontal distance on the terrain

corresponding to that line will be 10.2 x50 = 510m.

SECTIONS

Sections are the representation of the details of an object, which are located in a certain

section plane. In mine surveying practice, the most common types of sections are

geological sections and sections of mining workings which depict the enclosing rock,

some details of a working, supports and other objects. In sections, objects and details may

be projected onto vertical, horizontal or inclined planes.

PROFILES

Profiles are graphs depicting, in a vertical section, only the contour or part of the contour

of an object considered, for instance, the terrain relief, rocks in the roof or foot of a

working, haulage tracks, etc.



PROJECTIONS

These are graphical representations of particular spatial objects on the plane of drawings.

In mine surveying, orthogonal projections are preferably used, especially their variety

projections with numerical data.Orthogonal projections may be made on horizontal, vertical or inclined planes for more

clear representation, axonometric and affine projections are also employed.

SKETCHES

They are rough drawing of objects which are made by hand i.e without the use of rulers

and other drawing instruments. For instance, a mine survey makes sketches in the field

book when carrying out instrumental survey or taping of mining workings, measuring the

reserves of a mineral in store etc.

CLASSIFICATION OF DRAWINGS AND RULE OF MAPPING

As regards their compilation, all mine surveying drawings can be divided into

(1) Primary drawings: They are mapped directs by the result of a survey, which are

recalculated to a single coordinate system. Original (primary) drawing are the main

technical and juridical document for solving various problems of mining geometry.

Original graphical documentation should have an accuracy characterized by the data

as shown below:

S/No Error in Maximum value, mm

1 Mutual arrangement of intersection points of a

rectangular

± 0.2

2 Position of stations of a control or survey net

relative to the coordinate grid.

± 0.4

3 Mutual arrangement of the nearest stations of a

control or survey net

± 0.6

4 Position of conspicuous points relative to the ± 0.6



nearest stations of a control or survey net

5 Mutual arrangement of the nearest conspicuous

points.

± 0.8

2. Secondary drawings are prepared by reproducing (copying) the original drawing.

They must be complemented and correct when a need arises and can be used for

various practical purposes, for instance for the compilations of exchange and calendar

plans of mining work development, special plans for accounting the reserves, mines stock

and loss of a mineral, plans of mine ventilation, plan for the prevention of accidents, etc.

The main requirements of secondary graphical documents are that they should contain all

the essential information as refigured by the purpose and that this information should be

drawn clearly.

Graphical documentation should preferably be drawn on the scales;

1/500,1/1000,1/2000,1/50,00 or 1/10,00; the scale 1/25,000 is recommended for

cartograms and general charts, and scales 1/5.1/10/1/20,1/50,1/100 and 1/200 , for small

objects.

Processes and materials for reproduction of mining graphical documentation.

The principal processes for the reproduction of drawings of mining graphical

documentation are diazotpe copying, electrophotography, and offset printing.

1. Diazotype copying is the most popular process for the reproduction of original

drawings made on transparent materials . The original are reproduced on diazo-paper

and diazo-film. Light sensitive diazotype materials are manufactured industrially in a

wide range and differ from one another in the kind of a light- sensitive layer and base

and methods of development. Diazotype copying is performed in rotary copying

machines and copying frame.

2. Electrophotography is among the most advanced modern processes of reproduction of

graphical images. It is distinguished favourbaly by high productive facsimile

reproduction of image, simple technology, and possibility of copying of opaque



originals. Electro photographic process is based on the use of certain semiconductors

whose conduction changes under the effect of light.

3. Offset printing is the most efficient and simple process of the reproduction of

documents. Offset printing ensures a higher quality of printed graphicaldocumentation than is possible in diazotype copying on map paper and is well

suitable for making multicolour prints.

SYSTEM OF PLANE RECTANGULAR COORDINATES.

Geographic coordinates are expresses in angular values. They are inconvenient for

engineering calculations in geodesy and mine surveying. For this reason a system of

plane rectangular coordinates seems to be more convenient for land and mine surveying

and solving various engineering problems when their result should be plotted, can largely

simplify topographic and mine surveying adjustment of reference nets, calculation of

coordinates of reference points, processing of the results of surveys, etc.

The plane system of coordinates also ensures precise coincidence of plans of adjacent

areas, etc. The initial lines in a system of plane rectangular coordinates are mutually

perpendicular lines xx-yy lying in a horizontal plane and called respectively the axis of

abscissa (x-axis) and the axis of ordinates (y-axis). In contrast to mathematics, the axis of

abscissa in land and mine surveying plans is arranged vertically and coincides with the

direction of a meridian.

The intersection of these axes is the origin of coordinates (point O.) The coordinate axes

divided the plane of a drawing into four quadrant which are numbered clockwise

beginning from the quadrant in the north-east section ( as in the figure above ).

In land and mine surveying, the portions of the earth¶s surface measure up to 10km in

radius are considered to be flat. The larger areas of the earth¶s surface are depicted, to

minimize distortions, in special projection in which the earth ellipsoid is conventionally

developed on a plane the coincidence of both geographic and rectangular coordinates.



MINE COORDINATE SYSTEM

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

geodesy must be made used or applied.



CONTOURS AND THEIR INTERPOLATION

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:



y Set the map's agenda and select traits of the object to be mapped. This is the concern

of map editing. Traits may be physical, such as roads or land masses, or may be

abstract, such as toponyms or political boundaries.

y Represent the terrain of the mapped object on flat media. This is the concern of map projections.

y Eliminate characteristics of the mapped object that are not relevant to the map's

purpose. This is the concern of generalization.

y Reduce the complexity of the characteristics that will be mapped. This is also the

concern of generalization.

y Orchestrate the elements of the map to best convey its message to its audience. This is

the concern of map design.

Modern cartography is closely integrated with geographic information science (GIS) and

constitutes many theoretical and practical foundations of geographic information systems.

Scales: objects are depicted in mine surveying plans by diminishing the results of natural

(field) measurements. The degree of diminution of a line in a plan is determined by the

scale, i.e. a dimensionless fractional number in which the numerator is unity and the

denominator shows how many times a line depicted in the plan can be laid off along the

corresponding horizontal distance in the terrain. This is what is called the numerical scale

of lengths, or simply numerical scale. Consequently, s/S = 1/M, where M is the

denominator of the numerical scale.

In plans, numerical scales are written as simple fractions for example, 1/500, 1/1000, etc.

thus, if a numerical scale 1/1000 has been adopted for a plan, this means that horizontal

distances on the terrain will be diminished on the plan to one thousandth. It is

distinguished between large and small scales. A plan drawn on a larger scale can depict

more details of a locality.

The scale of a plan or map is chosen according to specifications and depending on where

the plan will be used. Distances on plans can be measured with an accuracy permitted by

the resolving power of man¶s eye, which is usually taken equal to 0.1mm (with the



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

contribution to its reading.



The working of the linear planimeter may be explained by measuring the area of a

rectangle ABCD. Moving with the pointer from A to B the arm EM moves through the

yellow parallelogram, with area equal to PQ×EM. This area is also equal to the area of

the parallelogram A"ABB". The measuring wheel measures the distance PQ(perpendicular to EM). Moving from C to D the arm EM moves through the green

parallelogram, with area equal to the area of the rectangle A"DCB". The measuring wheel

now moves in the opposite direction, subtracting this reading from the former. The net

result is the measuring of the difference of the yellow and green areas, which is the area

of ABCD. There are of course the movements along BC and DA, but as they are the same

but opposite, they cancel each other on the reading of the wheel.

Linear planimeter polar planimeter

INTERPRETATION OF MAPS AND PLANS

Map Projections

A map projection is any method of representing the surface of a sphere or other three-

dimensional body on a plane. Map projections are necessary for creating maps. All map

projections distort the surface in some fashion. Depending on the purpose of the map,

some distortions are acceptable and others are not; therefore different map projections

exist in order to preserve some properties of the sphere-like body at the expense of other

properties. There is no limit to the number of possible map projections. For simplicity,

this article usually assumes that the surface to be mapped is the surface of a sphere.

However, the Earth and other sufficiently large celestial bodies are generally better

modeled as oblate spheroids, and small objects such as asteroids often have irregular



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

type of hazardous zone.



HORIZONTAL SURVEYS OF UNDERGROUND WORKINGS

The principal sources of mine surveying are;

1. Underground workings (opening, preparatory, development, stopping ,

draining, exploratory , etc).2. Boreholes (prospecting, operating, unwavering, water observation, etc).

3. Boundaries of safe mining work, safety and barrier pillars.

4. Contours of inundated, gas laden, and caved workings, centre of

underground fires, isolating partition and other ventilation structure, gas

blower sites, areas and contours dangerous in gas or rock outbursts, rock

bump, water inrush, floating earth, source of underground water, etc;

5. Characteristics points of bedding elements of mineral deposits

6. Point for documentation of geological disturbances and other textural and

structural characteristics of deposits and enclosing rocks;

7. Point of mineral assaying

8. Location of surface and underground artificial structures and stationary

equipment in underground workings.(hoists, explosive store, informative

sheds)

The errors permissible in the measurements of horizontal and indignation angles and

side lengths in polygon metric traverses can be characterized by the data given below.

RMs error of

measured

horizontal

angle $M

RMs error of

measured

indication

angle ; MV

Coefficient of

influence in

linear

measurements

Length

independent

component ,

V

Random Systematic P

20´ 30´ 0.001 0.00005 0.01



Horizontal underground surveys

The principal kind of horizontal survey in underground workings is theodolite surveying

which consists of angular and linear measurements and subsequent calculation of the

rectangular coordinates x, y of survey points .Theodolite traverses may be divided into free and non-free.

Free theodolite traverses are referenced to only one point with fixed coordinates

and one fixed direction angle ; they may be stretched (fig 5.1a) or broken

controlled by a repeated theodolite survey closed traverses (fig 5.1c) are

controlled by comparing the sum of the measure angles and the sum of

coordinate increases with their analytical values

Non free theodolite traverses have redundant initial data. They can begun;

(a) Between the fixed points and fixed direction angles; in that case complete

control is ensured in terms of direction angles and coordinates (fig 5.1d).

(b) Between the fixed direction angles with the initial coordinates of one point,

i.e. with control in terms of direction angles (fig 5.1e).

(c) Between two points with fixed coordinates and with an initial direction angles

i.e. with control by the coordinates of the fixed points ( fig 5.1f) ; and

(d) Between two points with fixed coordinate with the initial direction angle

being unknown, in that case, control is possible by the length of the closing

line of the traverse (fig 5.1g).

In case under (b), (c) and (d) a complete control of whether a theodolite traverse has

been run properly is not ensured because of which a repeated traverse is run or the

lines and angles are measure run or the lines and angles are measure repeatedly.

Horizontal surveys in underground workings may involve certain difficulties which

increase labour consumption, reduce the accuracy of measurements, and increase the

error accumulation. Among the principal factor, causing such difficulties are; continuous

mobility of the underground objects being surveyed and rock displacement around

workings resulting in uncertain spatial position of permanent survey points underground;

certain limitations in selecting the most favoruable shapes of theodolite traverses and the



best lengths of traverse sides; constricted conditions for surveying in underground

working; poor illumination of working places; dust laden atmosphere in mines.

In order to minimize the influence of the factors indicated on the accuracy of surveys and

to avoid unproductive labour expenditure, it is essential to adhere to the following main principles in surveying work,

1. Mine surveying should proceed from the more general and more precise procedure to

more particular and less accurate work.

2. In any kind of surveying work, all measurement must be done with the optimum

accuracy sufficient for the purpose.

3. Mine surveying must be carried out under an appropriate and timely control both of

the field and in the office analysis of the results of survey.

For reliable and efficient performance of mine surveying, it is essential before starting

the work, to study can fully the conditions of the field work to draft the plan of

construction of survey traverses by the results of reconnaissance and consider in it the

existing peculiarities, narrow` place, etc; to determine the set of surveying instruments

and equipments, to test and adjust the instrument, to assign performers for the survey

work plan, and, when required, to make preliminary calculation of the accuracy of

surveys.

VERTICAL SURVEYS IN UNDERGROUND WORKINGS

Vertical survey, or leveling is a survey procedure in which the height difference of

some points over other are measure in a certain sequence, and then the required height

of point are calculated from the height of initial points and the height difference

measured.

This can be made by two methods which include:

(i) Geometric or direct leveling

(ii) Trigonometric or indirect leveling

The former method is employed in underground workings with small inclination angles

(up to 50) and the latter in steeper working.



The height transfer by geometric leveling should satisfy the following requirements.

a. The discrepancies of measured heights of points should not exceed 50mm in

polygonometric traverses or 80mm in theodolite traverses ( where L is the length of a

traverse line. Km)

b. Staff spacing should not exceed 200m in length and differ from one another by more

than 10m.

c. leveling lines between the initial bench marks should be close or run forward and

back.

d. the discrepancies of height difference at a station, as read off on the black and red

face of staff or at two different settings of the level instrument, should not exceed

10mm, and.

e. before starting the leveling procedure the available station points should be checked

for stability.

The discrepancies between the height difference established earlier and the test one

should not exceed 10 and 20mm respectively in polygon metric and theodolite traverses.

When transferring the height marks in underground working by trigonometric leveling,

the following accuracy requirements should be observed.

a. The permissible discrepancy of a zero offset in the measurements of indignation

angles is 1.51 in polygonmetric traverses;

b. The discrepancy of height difference determined for a line by leveling form and

back should be not more than 1/2000 of the side length in polygonometric traverses

or 1/1000 in theodolite traverses;

c. The discrepancy of two measured heights of theodolite and signals should be not

more than 5mm in polygonometric traverses or 10mm in theodolite traverses; and

d. The discrepancy in the height differences of the entire line of levels in polygon metric

traversing should be in polygonometric traversing should be not more than;

1/n + sin2S/3



Where (s) is the total inclined length of the forward and back traverese; m; n is the

total number of sides in the forward and back traverses.

S= mean indignation angle of traverse sides.

In theodolite traversing this discrepancy should be not more than 120mm

PRACTICALS

Distance measurements

The standard device for measuring distance in surface or underground tranverses is the

steel tape. In mine surveying, the distances commonly are measured along the line of

sight from the horizontal axis of the telescope to the sighting point. This is known as

slope chaining. The technique is preferred to horizontal chaining because of the frequent

steeply inclined lines of sight and because of its higher accuracy. The tapes used are of

20, 30, and 50m. The best steel tape is the 50m; because it increases the rate of

measurement and accuracy. Ordinarily transversing work seldom requires correction for

temperature or precise control of the pull. These factors must be taken into consideration

for very precise work such as in determing the exact length of a base line for

triangulation.

Leveling Transversing (with tapes and total stations)

Vertical surveys or leveling is a survey procedure in which the height differences

(elevations) of some points over others are measured in a certain sequence and then the

required heights of points are calculated from the heights of initial points and the height

differences measured. As regards to surface mining, leveling is the operation required in

the determination or more strictly, the comparison of height of points on the surface of



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.

Consider two points A and B as shown below:



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

= 131.702 3.484

= 128.218m AOD



General Procedure:

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

foresight on point G. this procedure is repeated

until the requires levels have been obtained.



BOOKING: Rise and Fall method

The readings are booked in a level book which is specially printed for the purpose as

shown below.

The booking of the Rise and fall systemB.S I.S F.S Rise Fall R.L Distance Remark

o.663 98.760 B.M=98.760

1.946 1.283 97.477 0 STAFF

STATION

A

1.008 0.938 98.415 20 B

1.153 0.145 98.270 40 C

2.788 1.585 0.432 97.838 60 D

CHANGE

POINT

2.270 0.517 98.355 80 E

1.218 1.052 99.407 100 F

0.646 0.572 99.979 120 G

3.350 2.231 3.079 1.860 Last R.D

2.231 =99.979

(- R.D of O.D)

-98.78

1.219

As a check on the arithmetic involved in reducing the levels, the backsightd and

foresights and the rises and falls must be summed up.

The checks are then:

(Backsights) - (Foresights) = (Rises) - (Falls) = Last R.L First R.L.

It must be pointed out that these checks concern only the accuracy of the reductions and

have no effect on the accuracy of the recordings themselves.



Height of collimation method

B.S Intersight Foresight Height of

collimation

Reduced

level

Distance Remarks

0.663 99.423 98.760 B.M 98.76

O.D

1.946 97.477 0 STAFF AT

A

1.008 98.415 20 B

1.153 98.270 40 C

2.787 1.585 100.625 97.838 60 D

CHANGE

OF POINT

2.270 98.355 80 E

1.218 99.407 100 F

0.646 99.979 120 G

3.450 2.311 99.979

-2.231 - 98.760

1.219 1.219

The height of collimation is obtained by adding the staff reading which must be a

backsight to the known R.L of the point on which the staff stands. All other readings are

deducted from the height of collimation until the instrument setting is changed,

whereupon the new height of collimation is determined by adding the backsight to the

R.L at the change point.

The arithmetrical checks to be applied to this system of booking are:

(B.S) - (F.S) = Last R.L First R.L



(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



produces a force on the gyro, to which it reads by swinging its north end toward north.

The momentum of the gyro causes it to over swing and thus to oscillate about the

astronomical north line. The techniques of observation vary somewhat among the

different types of instrument, but the basic approach is to find the mean position of theswing from a series of observations.

The physics of the gyro do not permit the theodolite to be used in the erect and inverted

positions. Consequently, these must be determined by setting up the instrument on a line

of known azimuth, obtaining the angle from that liune that line to astronomical north as

indicated by the gyro and using the difference as the correction factor.

This work is commonly done on the surface before taking the equipment underground.

Having determined the correction constant to be uused, the surveyor takes the equipment

underground to the place where the azimuth is to be determined. Setting up under one

permanent point to the backsights another, preferably several 30m away. He then brings

the gyro up to the speed, uncages it and proceeds to find the exact angle between his line

and true north. Applying his correction he now has the true azimuth of fixed line. He will

normally repeat the operation from other end as a check. When not in operation, the

gyroscope assembly is anchored within the instrument. The electrically powered

gyroscope is started while restrained and then released for operation. During operation

the gyroscope is supported within the instrument assembly, typically on a thin vertical

tape that constrains the gyroscope spinner axis to remain horizontal. The alignment of the

spin axis is permitted to rotate in azimuth by only the small amount required during

operation. An initial approximate estimate of the meridian is needed. This might be

determined with a magnetic compass, from an existing survey network or by the use of

the gyro-theodolite in an extended tracking mode.



A gyroscope mounted on a theodolite

Although a gyro-theodolite functions at the equator and in both the northern and southern

hemispheres, it cannot be used at either the North Pole or South Pole, where the Earth's

axis is precisely perpendicular to the horizontal axis of the spinner and the meridian is

undefined. Gyro-theodolites are not normally used within about 15 degrees of the pole

because the east-west component of the Earth¶s rotation is insufficient to obtain reliable

results. Unlike an artificial horizon or inertial navigation system, a gyro-theodolite cannot

be relocated while it is operating. It must be restarted again at each site.

The GPS instruments

The Global Positioning System (GPS) is a space-based global navigation satellite system

(GNSS) that provides location and time information in all weather, anywhere on or near

the Earth, where there is an unobstructed line of sight to four or more GPS satellites. It is

maintained by the United States government and is freely accessible by anyone with a

GPS receiver with some technical limitations which are only removed for military users.

With the advent of the Global Positioning System (GPS), elevation can also be derived

with sophisticated satellite receivers, but usually with somewhat less accuracy than with

traditional precise leveling. However, the accuracies may be similar if the traditional



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

connecting an extra antenna to it.

mine surveying compile

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