Venance_report

THE UNIVERSITY OF DODOMA
School of Mines and Petroleum Engineering
DEPARTMENT OF MINING AND MINERAL PROCESSING
B.Sc. MINING ENGINEERING
PRACTICAL TRAINING 3
AT
WILLIAMSON DIAMONDS LIMITED-MWADUI
Name: KITALY VENANCE D.
Reg. No: T/UDOM/2009/08472
Signature:……………………… Submission Date:…………………
Supervised by: Eng. SIXTUS MASOTA

i ACKNOWLEDGEMENTS | © KITALY VENANCE D. (UDOM 2012)
ACKNOWLEDGEMENTS
I would like to give my sincere grateful concern to the Almighty God for giving me strength,
health, consciousness and most of all the gift of life for which I have been able to perform
this task.
I am also very grateful to my father Mr. Daniel Kitaly and my lovely mother Mrs. Patricia
Daniel for their unconditional loving and care that they have given to me since I was a little
child until now. They have always been a part of my life and it would have been absolutely
impossible for me to get where I am now without their efforts.
I would also like to thank my PT supervisor Eng. Sixtus Masota for being a very important
part of my practical training at WDL. He always gave me all technical advice I needed and
where other experts were needed he helped me find them.
I wouldn’t forget to give my sincere appreciation to Mr. Venance Msabila, Mr. Mapunda
and Mr. Israel Wikech from the WDL production office, Mr. Timothy Kabondo, Mr.
Mandella and Mr. Salum from the WDL geology and survey office and Mr. Renatus from
Caspian project quality survey department. These people have really been very helpful to me
both socially and academically from the very first day of my practical training at WDL.
Special thanks to the School of Mines and Petroleum Engineering, The University of
Dodoma, as they are doing a very great job in providing us with quality education
theoretically but again struggle so much in getting the practical training places and allocate
them to us.
Finally I would like to thank my fellow colleagues, B Sc. Mining Engineering 4th
year for
their helpful cooperation which has always kept us going forward together as a class, and it’s
my great hope that we will get through this together and finish our studies successfully.

ii ABSTRACT | © KITALY VENANCE D. (UDOM 2012)
ABSTRACT
This report aims to explain the practical training observations made at WDL during the eight
weeks of my practical training.
The objectives of this report were to explain the mining operations that took place at WDL
(drilling, blasting and material handling), to study the economics of the company (especially
costs incurred and equipment’s production) and to perform a small project on the
productivity of loading and hauling equipment.
Direct observations on the drilling, blasting and material handling operations were done and
also questionnaires were used to obtain some information from different company sources
especially data concerning treatment plant performances and cost estimates for the month of
July. Some information was also obtained from various sources as secondary data including
some formulae and principles from different books and articles.
During the observation, data concerning excavators and trucks’ performances were taken by
using stopwatch and tabulated in appendices of this report. Drilling and blasting data were
also collected and presented in appendices of this report. Some mathematical formulae and
Microsoft Office (Excel) software were used to make analysis on the obtained data.
The specific findings for the project were as follows; excavator capacity was 2m3
and its
optimal cycle time was 26.3132sec, while the optimal trucks’ cycle time was 14minutes and
the optimal number of cycles per hour was 4. However the actual cycle time was more than
30 minutes and the resulting cycles per hour were 2. It was also found that a very long time
was spent by trucks queuing at dumping place.
Some more general findings were as follows; the tonnage of material handled as indicated by
production survey for the month of July and Caspian figures agreed to within 0.072% and the
powder factor for the observed blasting was 0.975kg/m3
.
The conclusions for the project were that; the material handling equipment were
underutilised and the productivity was low. Poor plant performance, poor blast fragmentation
and the small truck capacity were the main causes of underutilisation. The general conclusion
was that a detailed study on the blasting parameters should be done to see if they could be
altered to improve fragmentation. It was also concluded that production surveys were a good
approach for estimation of monthly production for Caspian payment issuing.
It was recommended to establish the ROM pad for productivity improvement. It was also
recommended to increase the trucks’ capacity to at least 30tonnes and that, the treatment
plant should be re-established to include the crushing system for productivity improvement
and cost reduction in explosives and material handling.

iii TABLE OF CONTENTS | © KITALY VENANCE D. (UDOM 2012)
TABLE OF CONTENTS
ACKNOWLEDGEMENTS ....................................................................................................................i
ABSTRACT........................................................................................................................................... ii
TABLE OF CONTENTS ...................................................................................................................... iii
1.0 INTRODUCTION............................................................................................................................1
1.1 LOCATION...................................................................................................................................1
1.2 BACKGROUND OF THE COMPANY.........................................................................................2
1.3 ORGANIZATION STRUCTURE ..................................................................................................3
2.0 DIAMONDS GEOLOGY ................................................................................................................4
2.1 KIMBERLITE FORMATION........................................................................................................4
2.2 ALLUVIAL DIAMONDS ..............................................................................................................6
3.0 MINE CYCLE..................................................................................................................................7
3.1 DRILLING....................................................................................................................................7
3.1.1 Marking the drilling pattern..................................................................................................7
3.1.2 Drilling the holes...................................................................................................................8
3.2 CHARGING..................................................................................................................................8
3.2.1 Making a primer....................................................................................................................9
3.2.2 Charging (loading) the hole ................................................................................................10
3.2.3 Tying/Hooking up the charged holes...................................................................................11
3.3 BLASTING..................................................................................................................................12
3.4 LOADING...................................................................................................................................13
3.5 HAULAGE..................................................................................................................................14
4.0 MINE SAFETY AND ENVIRONMENT......................................................................................15
4.1 SAFETY GEARS.........................................................................................................................15
4.2 MINE DUST AND CONTROL ...................................................................................................15
4.3 COMPANY’S SAFETY AND ENVIRONMENT STRATEGIES ..................................................15
5.0 ECONOMIC ASPECTS.................................................................................................................16
5.1 PRODUCTION SURVEYS .........................................................................................................16
5.1.1 Principle of operation of Differential GPS..........................................................................16
5.1.2 Setting the instrument..........................................................................................................17

iv TABLE OF CONTENTS | © KITALY VENANCE D. (UDOM 2012)
5.1.3 Taking measurements..........................................................................................................17
5.1.4 Accessing and analyzing the data........................................................................................17
5.1.5 Computing the production...................................................................................................17
5.2 LOADING EQUIPMENTS PRODUCTION...............................................................................18
5.3 HAULAGE EQUIPMENTS PRODUCTION..............................................................................18
5.4 EQUIPMENTS AVAILABILITY AND UTILIZATION................................................................18
5.5 COST ESTIMATES.....................................................................................................................19
6.0 PT PROJECT .................................................................................................................................20
6.1 TITTLE .......................................................................................................................................21
6.2 PROBLEM STATEMENT...........................................................................................................22
6.3 OBJECTIVES .............................................................................................................................23
6.3.1 Main Objective ....................................................................................................................23
6.3.2 Specific Objectives...............................................................................................................23
6.4 LITERATURE REVIEW..............................................................................................................24
6.5 METHODOLOGY ......................................................................................................................25
6.6 DATA COLLECTION AND ANALYSIS......................................................................................26
6.7 RESULTS AND DISCUSSIONS .................................................................................................28
6.7.1 Results .................................................................................................................................28
6.7.2 Discussions..........................................................................................................................28
6.8 CONCLUSIONS .........................................................................................................................31
6.9 RECOMENDATIONS.................................................................................................................32
7.0 GENERAL RESULTS AND DISCUSSIONS...............................................................................33
7.1 RESULTS....................................................................................................................................33
7.2 DISCUSSIONS ...........................................................................................................................34
8.0 CONCLUSIONS............................................................................................................................36
9.0 RECOMMENDATIONS ...............................................................................................................37
10.0 NOMENCLATURE.....................................................................................................................38
11.0 REFFERENCES...........................................................................................................................39
12.0 APPENDICES..............................................................................................................................40
Appendix 1: Production Survey data and analysis...........................................................................40
Appendix 2: Loading equipments performances ..............................................................................43
Appendix 3: Haulage equipments performances..............................................................................45

v TABLE OF CONTENTS | © KITALY VENANCE D. (UDOM 2012)
Appendix 4: Excavator utilization computations..............................................................................49
Appendix 5: Drilling observations ...................................................................................................50
Appendix 6: Blasting statistics .........................................................................................................51
LIST OF TABLES
Table 12.1: Part of the production survey data for the month of July...................................................40
Table 12.2: Excavator (Pc-Komatsu) operations at SW Block C (03/08/2012)....................................43
Table 12.3(a): Dump Trucks statistics (06/08/2012, NW Block B to Scalp Bin).................................45
Table 12.3(b): Detailed study on DT 41 at NW Block C (27/08/2012, 9a.m to 4p.m).........................45
Table 12.5: Drilling statistics at NW Block C.......................................................................................50
LIST OF FIGURES
Fig. 1.1: Tanzania map showing location of Mwadui.............................................................................1
Fig. 1.3: Petra Diamonds’ Group Structure.............................................................................................3
Fig. 2.1(a): Initial eruption of K2 and KT and late intrusion of K1.........................................................4
Fig. 2.1(b): Late intrusion of K1 Pyroclastics.........................................................................................4
Fig. 2.1(c): Formation of RVK................................................................................................................5
Fig. 2.1(d): Formation of shale and Bouma facies..................................................................................5
Fig. 2.1(e): Deflation deposit (SOP and SAP)........................................................................................5
Fig. 2.1(d): Mwadui pipe geology outlook..............................................................................................5
Fig. 2.2: Excavator mining alluvial diamonds.........................................................................................6
Fig. 3.1(a): A part of drilling pattern in the SW Block C of the Mwadui pit (plan view).......................7
Fig. 3.1(b): Drilling at Mwadui pit..........................................................................................................8
Fig. 3.2(a): Emulsion truck (loaded at magazine)...................................................................................9
Fig. 3.2(b): Charging the holes at site.....................................................................................................9
Fig. 3.2(c): Primer (cross section)...........................................................................................................9
Fig. 3.2(d): Charged hole (section)........................................................................................................10
Fig. 3.2(e): Charged holes tied up (colours correspond to delay time; time in milliseconds)...............11

vi TABLE OF CONTENTS | © KITALY VENANCE D. (UDOM 2012)
Fig. 3.3: Blasting taking place at Mwadui pit.......................................................................................12
Fig. 3.4: Libher excavator loading the dump truck at SW Block C......................................................13
Fig. 3.5: Dump truck hauling material..................................................................................................14
Fig. 7.2: surveyor’s path vs the actual required path (in a section of water trench at NW pit).............34
Fig. 12.1(a): Worked out areas for the month of July (modelled by the aid of model maker system
software)................................................................................................................................................41
Fig. 12.1(b): The Mwadui pit DTM......................................................................................................41
ATTACHMENTS
Attachment 1: Certificate of work showing different costs incurred in July
Attachment 2: Drilling and blasting costs for the month of July
Attachment 3: Load and haul to scalp cost per tonne for the month of July
Attachment 4: Daily report logbook
Attachment 5: Training Certificate

1 CHAPTER 1 | © KITALY VENANCE D. (UDOM 2012)
CHAPTER 1
INTRODUCTION
Williamson Diamond Limited (WDL) is an open pit mine and is the largest operating
diamond mine in the world, found in Tanzania. Mining activities in WDL are divided into
two distinct operations which are
 In-pit mining; this involves mining within the kimberlite pipe through open pit
mining and
 Alluvial/Gravel mining; this involves mining of alluvial/placer diamonds which
have been eroded from their area of origin and get deposited somewhere else. This is
done by removing the upper dark soil to uncover the diamond hosting soil which is
then treated to recover the diamonds in it.
1.1 LOCATION
WDL is located at Mwadui area in Kishapu District in Shinyanga region. Mwadui is located
at a few kilometers from Shinyanga – Mwanza road, and just several kilometers from a small
town known as Maganzo. The climate of Mwadui is dry and semi-arid having two seasons,
namely, wet season (Nov to Apr) and dry season (May to Oct). Average temperature varies
from 17 degrees centigrade to 33 degrees centigrade.
Fig. 1.1: Tanzania map showing location of Mwadui

2 INTRODUCTION | © KITALY VENANCE D. (UDOM 2012)
1.2 BACKGROUND OF THE COMPANY
In 1940, Dr. John Thoburn Williamson, a Canadian mining Geologist discovered the Mwadui
kimberlite after many years of exploration, and in 1942, he formed Williamson Diamonds
Limited with himself as the sole shareholder, managing director and General Manager.
He died in 1958 and after his death the Tanganyika Government and Willcroft Company took
over the Company jointly each holding 50% of shares. Due to its wide experience in mining
industry, Willcroft Company managed the mine until 1973 when the Government, under
STAMICO took over that role and a Tanzanian management team was appointed.
In 1993, Willcroft Company entered into negotiations with Government of Tanzania on how
best to rescue the mine from imminent liquidation. Both parties reached an agreement in
October 1994 where by Willcroft raised its shareholding to 75% by buying 25% of the
Government’s shares and also made available loan funds to pay creditors, and to refurbish
the mine and bring it back into profitability like before.
During 1995, the mine underwent a major capital rehabilitation programme. The project
entailed the construction of new treatment plant. The installation of modern recovery
equipment and security system in the recovery house, the overhaul of mining machinery and
power generating equipment were done. The company carried out the work of upgrading and
modernizing the water treatment plant to ensure clean and safe drinking water is available to
Mwadui residents and part of his neighbours.
For more than 60 years Williamson Diamonds Limited was one of major contributors to the
country’s foreign exchange earnings. Up to 2010 the mine has produced more than 20
million carats worth several hundred million US dollars. Mwadui mine has got huge deposit
(resource) which can be mined for the coming 20 years to about 205 meters from the surface.

3 INTRODUCTION | © KITALY VENANCE D. (UDOM 2012)
1.3 ORGANIZATION STRUCTURE
Fig.1.3: Petra Diamonds’ Group Structure

CHAPTER 2
DIAMONDS GEOLOGY
Most diamonds are over three billion years old, two-thirds the age of the Earth. The most
recent kimberlite volcano eruption was approximately 53 million years ago. Diamond (from
Greek word adamas, meaning “unbreakable”) is an allotrope of carbon, where the carbon
atoms are arranged in variation of the face-centred crystal structure (diamond lattice). That
means diamond is purely composed of carbon. Diamond has inert chemical nature, most hard
known mineral and has a fairly high specific gravity.
2.1 KIMBERLITE FORMATION
The Mwadui Kimberlite pipe was formed more than 52 million years ago. The pipe was
formed from high pressure and temperature magma in the upper mantle, where the molten
magma undergone differentiation as it was rising upward (Volcanic eruption) to the surface
through fracture and cavities resulting into emplacement of tuffaceuos rim in both sides of
the crater i.e Volcanic Eruption. Most of the diamondiferous kimberlite deposits originate at
a depth between 150 – 300 Km in the upper mantle. Currently Mwadui pipe is the largest
known economically exploitable Diamond bearing kimberlite pipe in the world.
Fig. 2.1(a): Initial eruption of K2 and KT Fig. 2.1(b): Late intrusion of K1 Pyroclastics
and late intrusion of K1
Granitic basement
+
+
+
+
+
+
Fracturing ofwall-rock
due to pipe emplacement
+
+
+
+
+
+
Largertuffrimin the westcompared to the east
+
+
Pyroclastic deposits from
main eruption
Late intrusion ofK1,projected
fromsouth-wall
K2/KT
Graniticbasement
+
+
+
+
+
+
Fracturingofwall-rock
duetopipeemplacement
+
+
+
+
+
+
+
+
Pyroclasticdepositsfrom
maineruption
LateintrusionofK1,projected
fromsouth-wall
K2/KT
Failureofcraterwallsandentryof
mixedgraniteandkimberliticejecta
Wall-rockandtuffring
failure=BVK
Wall-rockfailure=GB

5 DIAMONDS GEOLOGY | © KITALY VENANCE D. (UDOM 2012)
Fig. 2.1(c): Formation of RVK Fig. 2.1(d): Formation of shale and Bouma
facies
Fig. 2.1(e): Deflation deposit (SOP and SAP) Fig. 2.1(d): Mwadui pipe geology outlook
Granitic basement
+
+
+
+
+
+
Fracturing ofwall-rock
due to pipe emplacement
+
+
+
+
+
+
+
+
Pyroclastic deposits from
main eruption
Late intrusion ofK1,projected
fromsouth-wall
K2/KT
Tuffring
failure =RVK
Grain-flow processes dominate
within the RVK.Dominantalong
the western margin due to greater
volume ofejecta.
Craterwalls have retreated to stable
positions with less frequentcollapse
Tuffring
failure =RVK
Graniticbasement
+
+
+
+
+
+
+
+
+
+
+
+
+
+
maineruption
fromsouth-wall
K2/KT
Craterlake
Inflow offine-grainedgraniticdebris
andkimberliticejectaintoacrater
lakeenvironmentwithperiodic
transgressionandregressionoflakelevel
Boumafacies
Graniticbasement
+
+
+
+
+
+
+
+
+
+
+
+
+
+
maineruption
fromsouth-wall
K2/KT
Lastremainingmaterialfromthetuffringsortedand
concentrated throughwindandwateraction
toformSOPandSAPgravels.
N shale
bouma
K2K
t
K
1
G
B
R
V
B
V

6 DIAMONDS GEOLOGY | © KITALY VENANCE D. (UDOM 2012)
2.2 ALLUVIAL DIAMONDS
Some more years after formation, the Kimberlite was emplaced into the granites, Granitic
gneiss, mica schist and dolerite dikes of the Achaean granitoid shield followed by failure of
country rock and tuff ring due to gravitation forces, rain, wind action and active streams
flowing leading into weathering, erosion, transportation and deposition forming alluvial/
gravel deposit away from the kimberlite pipe.
Fig. 2.2: Excavator mining alluvial diamonds

CHAPTER 3
MINE CYCLE
In WDL the mining activities took place in an open pit mine and included drilling, charging,
blasting, loading and hauling the blasted material to the scalp bin of the treatment plant.
3.1 DRILLING
Drilling in WDL was done by drill rigs that employed Down The Hole (DTH) drilling. The
holes drilled were normally 102mm in diameter and ranged between 5m and 8m in depth.
3.1.1 Marking the drilling pattern
At WDL drilling pattern used was normally staggered pattern with spacing 2.5m and burden
2.5m. Exact location and depth of each drill hole was established by the aid of surveying.
Total station was normally used for this task. Depending on the relief of the surface being
marked, holes could have different depths so as to ensure the level ground after blasting.
Fig 3.1(a): A part of drilling pattern in the SW Block C of the Mwadui pit (plan view)

8 MINE CYCLE | © KITALY VENANCE D. (UDOM 2012)
3.1.2 Drilling the holes
The holes were drilled at different time intervals depending on the rock types encountered by
the drill bit in its way through the hole. Drilling rate was bigger in kimberlitic rocks where
the drill chips of up to 1cm diameter were produced, and it was very small in granitic
segments where the white dust was produced.
Part of the drilling statistics were taken during drilling at NW Block C, including drilling
time, drill steel changing time, manoeuvring time and delay time and description for each
incidence. All these information were tabulated in table 12.5 (appendix 5). From the data, the
average drilling time per hole could be found to be 7.74min; but this result was affected
much by DH6 where granitic sections were encountered.
Fig. 3.1(b): Drilling at Mwadui pit
3.2 CHARGING
In WDL the charging process was done by a special truck which used high pressure
mechanism to force explosives into holes through a loading pipe. The main charge used was
emulsion (for wet holes) and ANFO was used in dry holes.
Emulsion has higher density than water, thus it displaces water from the hole and make
successful charging without changing its detonation properties. However, emulsion is
expensive than ANFO and its uses had to be optimised. All water free holes were thus
observed and charged by ANFO while emulsion was used only in wet holes.

Boosters were also used to detonate the main charge. The busters were made up of mixture of
trinitrotoluene (TNT) and Pentaerythritol tetranitrate (PETN) together called pentolite.
Fig 3.2(a): Emulsion truck (loaded at magazine) Fig 3.2(b): Charging the holes at site
3.2.1 Making a primer
A primer was normally made by inserting a detonator into pentolite booster. The detonator
was inserted into the booster in such a way that it tightened and couldn’t be pulled out easily.
This was important because during addition of the main charge, the cord of the detonator was
pulled a bit to put it straight so as to avoid any bend which could lead to detonation cut off.
Fig 3.2(c): Primer (cross section)

3.2.2 Charging (loading) the hole
Primer was inserted into the hole, and then the main charge was pumped into the hole while
holding the connecting cord straight up. After charging a required length (charge length) the
remaining part of the hole was stemmed using drilling chips. Ideally the loaded hole should
look as shown below.
Fig. 3.2(d): Charged hole (section)

3.2.3 Tying/Hooking up the charged holes
Tying up of charged holes depends on the required direction of material to be blasted. The
blasting performed in WDL pit (SW Block C) and its tie up together with the desired
direction of the blasted material was summarised as shown in fig. 3.2(e).
Fig 3.2(e): Charged holes tied up (colours correspond to delay time; time in milliseconds)

3.3 BLASTING
The charged and properly hooked up pattern (as shown in fig. 3.2(e)) was initiated by
electrical charge using the blasting machine. The electrical charge passed through the
electrical cables and to the electrical detonator which transferred the detonation signal to the
detonating cord connected to the entire pattern as shown in figure 3.2(e).
Fig 3.3: Blasting taking place at Mwadui pit
All data concerning the blast (charge length, stemming length, number of holes, average
depth, holes’ diameter, spacing, burden, explosive density, number of delays, density of
blasted material etc.) were collected and recorded. From the data, powder factor used was
estimated (see appendix 6).

3.4 LOADING
Most of the time loading at WDL was done by excavators. The excavators used were of three
types; Pc-Komatsu (2 excavators @ 450t/hr), Libher (1 excavator @ 350t/hr), Cat 345 (1
excavator @ 350t/hr) and Cat 320 (1 excavator @ 200t/hr).
The operations of one of the Komatsu excavators at SW Block C of the pit were studied in
03/08/2012. The cycle time (time to dig, swing, empty material into the dump truck and
swing back to digging position) of the excavator, number of cycles/passes to full load a dump
truck and idling time of the excavator were all recorded and tabulated in table 12.2 (appendix
2).
Fig 3.4: Liebher excavator loading the dump truck at SW Block C

3.5 HAULAGE
At WDL haulage activities were done by dump trucks. The trucks used for hauling activities
were of two types; Cat 769 and DH 325-Komatsu (both had truck factor of 25t and capacity
of up to 150t/hr).
The trucks operations at NW Block B were studied in 06/08/2012. Loading time, travelling
time (to and from the scalp bin), queuing time (at loading and dumping areas) and
manoeuvring time were all obtained by means of stopwatch and tabulated in table 12.3. The
haul distance was also read from the trucks’ display and recorded (appendix 3).
Fig 3.5: Dump truck hauling material

CHAPTER 4
MINE SAFETY AND ENVIRONMENT
WDL was one of the companies which ensured and put a strong emphasis on the safety
issues. All workers at WDL were emphasised to ensure the safe working environment before
commencement of any task. It was known to each worker that safety was the most important
thing and was everyone’s responsibility.
4.1 SAFETY GEARS
WDL provided safety gears to her workers to ensure that they are all protected from
accidents (if they were to occur). Some of the safety gears offered were
 Safety boots
 Hard hat
 Goggles
 Reflectors
 Dust masks
 Ear plugs and
 Gloves
4.2 MINE DUST AND CONTROL
Any mining operation produces dust and this can reach dangerous levels if strong measures
to prevent and/or control the dust are not taken. Most of the mine dust is micro dust (with
particle size/diameter less than 5microns) and this can be very harmful to the worker if s/he is
exposed to such dust for a long time.
At WDL dust were produced from drilling, blasting, machines (trucks) movements and wind.
To avoid the problems indicated above, the working places and all roadways in the pit and
surrounding where large number of trucks and other vehicles often passed were sprayed
water to suppress dust. A special truck (water bowser) was used for this task.
4.3 COMPANY’S SAFETY AND ENVIRONMENT STRATEGIES
To ensure safety in working place WDL was doing the following
 Training; all workers were involved in safety training/induction after every vacation.
 Leading; leaders were to be an example of safe working mannerism.
 Controlling; there should be zero tolerance to any risky/unsafe conduit. The
responsible person(s) should be punished as by indicated in law.
 Motivating; if someone do so well in ensuring safety at his/her working place, s/he
should be awarded for that.

CHAPTER 5
ECONOMIC ASPECTS
WDL worked with several companies in her daily mining activities. Some of them were
Caspian Tanzania ltd (mining operations) and Zenit Security. These companies used a lot of
resources including money, and a careful economic study should be done by each individual
company in order to keep the business going.
5.1 PRODUCTION SURVEYS
Mining activities (drilling, blasting and material handling) in WDL were done by Caspian
Tanzania ltd. They were mining contractors for WDL and they were paid in terms of tones of
material mined and handled. In order to reach the compromise in terms of payments, both
sides (WDL and Caspian) estimated the amount of material handled and the two estimates
were required to coincide.
Caspian estimated the material handled by counting the number of dump trucks handled.
Since the trucks were rated with the truck factor of 25t, the tonnage of material handled in a
month could be estimated.
WDL estimated the production by using production surveys. These surveys were done
monthly by using Differential GPS and the results were used to estimate the tonnes of
material handled by Caspian so that they can be paid. The production survey for month of
July was done at the end of the month as described below.
5.1.1 Principle of operation of Differential GPS
Differential GPS is a surveying instrument which uses the satellite in specified channel to
take measurements of locations on the earth’s surface. The instrument is composed of the
following;
 Base
 Radio
 Rover and
 Controller
As the surveyor holding the rover and controller walks around the area to be surveyed, the
radio (set at a fixed position near the base) receives signals from satellite mounted in space
and sends the signals to the base (which is set and levelled at a known location). The base
again sends the information to the rover after processing the satellite signals and this
information is sent to the controller via Bluetooth.

17 ECONOMIC ASPECTS | © KITALY VENANCE D. (UDOM 2012)
5.1.2 Setting the instrument
The base of the instrument was set at a known point by the aid of stand, and the instrument
was levelled, and then set at the exact point by a cross-hair seen through small eyepiece on
the instrument (the cross-hair must coincide with the exact marked point on the ground). The
radio was also set near the base and the two were connected through a special cable. The
rover and controller were held by the surveyor and the system was switched on.
5.1.3 Taking measurements
Measurements of positions were done to get Eastings, Northings and Elevations of points on
the earth’s surface as the surveyor holding the rover and controller walked through the area
to be surveyed. Exact locations were determined by the satellite mounted in space and signals
were sent to the base through the radio, then to the rover and to the controller by means of
Bluetooth.
5.1.4 Accessing and analysing the data
After surveying the entire area, the controller was taken to the office and connected to the
computer. By using Trimble Geostatistics Office (TGO) the data were downloaded from the
controller into the computer.
The downloaded data were input into Model Maker System (MMS) as CSV data, with data
format y, x, z (Northings, Eastings, Elevations). This software performed computations and
analysis on the data and displayed a model of the surveyed area on the screen of the
computer. For more visualization, the contour and triangulation commands were used; this
gave a more vivid model of the surveyed area (see figure 12.1(a) in appendix 1).
5.1.5 Computing the production
The model obtained in the previous section was inserted in the pit DTM (figure 12.1(b)) of
the previous month (June). By using cut and fill command in MMS, the worked out areas
were shown clearly on the new pit DTM, and the software also calculated
 The cut volume and
 The fill volume
The difference between the two gave the production (volume of material mined and handled)
for the entire month of July. The volume obtained was then multiplied by the average density
of the material (2.01t/m3
) to get tonnage of material handled (see appendix 1).

5.2 LOADING EQUIPMENT PRODUCTION
Loading activities in WDL were mainly done by excavators. Sometime front end loaders
(FEL) were used, and bull dozers were also used to doze the muck-pile and make it suitable
for the loading equipment to handle. Among these equipment, a careful study was done on
the performance of one of the excavators (Pc-Komatsu at SW block C).
The cycle time of the excavator which included
 Digging,
 Swinging,
 Emptying material into the truck and
 Swinging back was obtained by the aid of a stopwatch.
These varied from cycle to cycle thus the average cycle time were calculated from the
individual cycle times (see appendix 2)
The number of cycles/passes to fill one truck was also counted and recorded (see table 12.2
in appendix 2)
The excavator production per
 Cycle
 Hour and
 Shift were calculated (see computations in appendix 2)
5.3 HAULAGE EQUIPMENT PRODUCTION
A careful study was done on dump trucks (CAT 769 and DH 325-Komatsu) and a more
concentrated study done on DT 41 (Pc-Komatsu), by obtaining its cycle times for the entire
shift (see table 12.3(b) in appendix 3)
The trucks’ production per cycle, hour and per shift was then estimated using the data
obtained (see computations in appendix 3)
5.4 EQUIPMENT’S AVAILABILITY AND UTILIZATION
Availability of equipment refers to the percentage time in which the equipment is available
and ready to work out of the total time for the entire shift.
Utilization of equipment refers to the percentage time during which the equipment is actually
in operation/production out of the available time of the equipment. It can also be referred to
as the time during which the equipment is actually in use for production.

Out of the equipment observed, the excavator in section 5.2 was also studied to see how long
it was available and how effectively it was utilized out of the time it were available (see
appendix 4 for computations).
5.5 COST ESTIMATES
One of the costs incurred by WDL was mining operations cost. These operations were
carried out by Caspian Tanzania ltd. Costs were thus incurred by Caspian and then WDL
paid to Caspian the costs they incurred plus 15% as the profit for Caspian. The cost here
covered the following;
 Material hauled costs; these were charged per tonne of material hauled where, the
number of truck/loads were counted and multiplied by truck factor (most of the time
this was 25t). WDL did production surveys to countercheck the Caspian figures in
this case.
 Loading equipment costs; these were charged per hours of equipment/plant in
operation. Equipment/plants here included excavators, FELs, bull dozers and graders.
All equipment mentioned were able to record the hours in operation and at the end of
each shift the hours were read and recorded.
 Drilling costs; these were charged per metres of holes drilled. WDL counterchecked
the holes’ depths using tape measures to ensure that the indicated depths/metres were
actually drilled.
 Blasting/explosives costs; these were charged per actual amount of explosives used
and by considering the actual explosive prices at the market at present time.
The total costs incurred by Caspian and resulting costs incurred by WDL for the month of
July were as shown in attachments 1, 2 and 3.

CHAPTER 6
PT PROJECT

21 PT PROJECT | © KITALY VENANCE D. (UDOM 2012)
6.1 TITTLE
IMPROVEMENT OF LOADING AND HAULING
EQUIPMENT PRODUCTIVITY

6.2 PROBLEM STATEMENT
Underutilization and overloading of loading and hauling equipment has been occurring
interchangeably at WDL and leads to poor production as well as increased costs of operation.

6.3 OBJECTIVES
6.3.1 Main Objective
 To determine the optimum performance of the loading and hauling equipment
6.3.2 Specific Objectives
 To determine the optimal excavator capacity to meet required production
 To estimate the optimal number of trucks per excavator
 To evaluate the optimal cycle time for both excavators and trucks
 To determine issues which prolong cycle time of trucks and suggest some measures
to resolve the issues

6.4 LITERATURE REVIEW
Caspian Tanzania ltd is a mining contractor for WDL and is responsible for all mining
activities (drilling, blasting, loading and hauling) in the company. These operations are
performed in an open pit mine established in the Mwadui kimberlite pipe. Most of the
materials encountered in this area are clays, shale, mudstone, granites and kimberlitic non
clay materials. The rock density varies between 1.88(for shale) to 2.55(for granites).
Loading is mainly done by excavators (Pc-Komatsu @450t/hr, Libher @350t/hr, Cat 345
@350t/hr and Cat 320 @200t/hr). The maximum number of trucks assigned to a single
excavator is four, and normally the excavators in pit do not exceed two.
Haulage of material is done by dump trucks (Cat 769 @ 25t and DH 325-Komatsu @25t)
which carry material from various parts of the pit to the scalp bin. At the scalp bin the
treatment plant draws material at a rate of 520t/hr. This is the required production because
the dumping is direct from trucks to the plant bin (no ROM pad for storing material before
feeding to the plant).
The direct dumping method has been the main cause of delays because the plant delays due
occur due to several reasons, causing terrible queuing of trucks at the scalping area and as a
result the loading equipment idles for significantly long time waiting for trucks to come back.

6.5 METHODOLOGY
Various methods were used for data collection in this project as well as the analysis of the
data which include;
 Direct observation of the loading equipment (excavators) and hauling equipment
(dump trucks) operations, whilst recording their actual time in operation and time for
delays/ queues by using stop watch.
 Travelling in one of the trucks to observe the velocity with which it was going as well
as the actual distance from the loading to the dumping area.
 Observation of the plants’ operations including its capacity (t/hr), delays and their
causes and its limitations in terms of type and size of material it can handle.
 Questioning the responsible site supervisors about the capacity of the excavators and
the dump trucks available at site.
 Use mathematical approach and excel software to analyse the data

6.6 DATA COLLECTION AND ANALYSIS
Pc-Komatsu excavator were observed at SW Block C (03/08/2012) and the data (obtained by
means of stopwatch) were tabulated as shown in table 12.2 (appendix 2).
Dump trucks operations at NW Block B were also studied (in 06/08/2012) and the data
(obtained by stopwatch) were tabulated in table 12.3(a) (appendix 3). The dump trucks
observed were DT18, DT19, DT21, DT23 and DT41.
In 27/08/2012 further study was done on DT41 at NW Block C (from 9a.m to 4p.m) and the
obtained data were recorded in table 12.3(b) (appendix 3)
The distances from the pit (NW Block B and NW Block C) to the scalp bin were also
obtained and recorded as shown in appendix 3.
The analysis on the excavator data showed that;
The average digging cycle time was 26.3231s
With this time, the excavator could make 137cycles/hr
The bucket fill factor of the excavator was 1.05, and its capacity was 2m3
This would yield the production of 2.1m3
/cycle
This was equivalent to 4.2tonnes (density of material was 2t/m3
)
The production per hour should be 575.4t and the resulting production per shift (8hrs)
should be 4603.2t (see computations in appendix 2)
This would be possible if the excavator was utilized effectively but again the analysis showed
that;
The availability of the excavator was 62.5% (5hrs) and it was utilized for only
27.78% (1.39hrs) (see appendix 4)
The analysis on the trucks showed that;
All trucks which worked at NW Block B on 06/08/2012 could make utmost 2cycles per hour.
Most of the cycle times were very long reaching up to 41.28min.
Considering the distance and permitted speed in pit the analysis showed that the optimum
cycle time was 13.48min (utmost 14min), and the optimum number of trucks per excavator
was found to be 4trucks (see appendix 3).

Further analysis on the DT41 data showed that the average cycle time were still very long
(30.07min). The analysis still showed that the cycle time could fall to 21.81min if the
queuing time at scalping area were removed, and this could still drop to 16.39min if the
excessively queuing time at the loading area were removed (with 1min as the maximum
allowable).
The analysis also showed that the average travel time (loaded and empty) was 5.49min and
4.36min respectively which made the average speed of DT41 for that day to be only
33.49km/hr (all computations in appendix 3).

6.7 RESULTS AND DISCUSSIONS
6.7.1 Results
The average digging cycle time for the excavator was 26.3231s
Production of the excavator (Pc-Komatsu) per cycle was 2.1m3
/cycle (4.2tonnes)
Production of excavator (Pc-Komatsu) per hour (if fully utilized) could be 575.4tonnes
The availability of the excavator was 62.5% (5hrs)
The utilization of the excavator was 27.78% (1.39hrs)
The maximum cycles trucks could make were 2cycles per hour
The optimum cycle time was 13.48min (utmost 14min).
The optimum number of trucks per excavator (Pc- Komatsu) was 4trucks
For Cat 345, the optimal number of trucks was 3 trucks
The cycle time (with queuing time at scalping area removed) was 21.81min
The cycle time (with 1min as the maximum allowable queuing time at loading area) was
16.39min
The average speed of DT41 (in 27/08/2012) was 33.49km/hr
6.7.2 Discussions
For the excavators;
Both excavators seemed to be underutilized if we consider their rated capacities. For example
Pc-Komatsu excavator with capacity 450t/hr could handle only 4trucks which could make a
maximum of 4 cycles per hour and had truck factor of 25tonnes.
This meant that, after one hour, the excavator would have loaded only 400tonnes while its
actual capacity was 450tonnes and above. Trucks capacities were thus a cause.
The underutilisation of the Pc-Komatsu excavator, together with the nature of material made
it necessary to use a second excavator (Cat 345) to meet the production requirements.
However, this excavator was also underutilized since it could handle only 3trucks and the
trucks could make only 3cycles per hour. This meant that the excavator would have loaded
only 225tonnes in an hour while its actual capacity was 350tonnes per hour.

The underutilization of these excavators was not only caused by the capacity of dump trucks,
but also the dumping mechanism and the treatment plant itself. The plant for instance had a
capacity of 520tonnes per hour which could be met by a single excavator (Pc-Komatsu could
load up to 575.4tonnes in an hour if it were fully utilized).
However the plant couldn’t handle clayish material (from NW Bock B and C) well, due to
their sticky property and some non-clay material (from SW Block C) were needed for
blending (to reduce the stickiness of clayish material). This made it necessary to use a second
excavator (Cat 345) for loading this blending material although both excavators were being
underutilized.
Excessive idle and/or delay time also seemed to be another cause for underutilization of
excavators. For example in 03/08/2012 at SW block B, the Pc-Komatsu excavator was
available for 62.5% and utilized for only 27.78%. The availability was reduced because the
excavator replaced the Cat 345 which normally worked in this place, and it was taken away
5hours later when the required excavator came back.
However, in these 5hours the excavator was idle for most of the time and resulted to severe
underutilisation of the equipment. A big percent of the idling time for the excavator was
caused by late arrival of dump trucks from the scalp bin, causing the excavator to spend a lot
of time waiting for the trucks to come back. Some other time was lost sorting the granite
boulders from the muck to facilitate loading.
The only time the excavators seemed to be over utilised was when the trucks came back in
quick succession from the scalp bin after a considerable queuing which altered the cycles of
the trucks, though it seldom happened
For trucks;
Trucks seemed to be fully utilized only when the plant was effectively in operation and the
muck pile consisted small amount of boulders. At such incidences the optimal number of 4
cycles per hour could be met. However this didn’t happen so often. Most of the time one
would encounter plant stoppages and delays and in the muck pile, significant amount of
granite boulders were inevitable.
The treatment plant poor performance seemed to be the main cause of trucks’
underutilization. From table 12.3(b) it could be seen clearly that this was a problem since
trucks sometimes had to queue for up to 35.25minutes waiting to dump material to the scalp
bin.

However this problem could be eliminated completely if the ROM pad was established near
the scalp bin and trucks would have to work even when the plant is off. This would still be of
advantage if in case the load and haul operations faced some bottlenecks since the plant
could still be fed by material from ROM pad.
Poor blasting leading to too much boulders in the muck pile was also seemed to be the cause
of underutilization of dump trucks (as well as excavators). Sometimes trucks had to stay in
queue for long time while the excavator sorted the boulders from the muck pile. Again if by
any chance, the boulder passed the scalper grizzles and entered the scrubber feed bins in the
treatment plant, blockage of the bins occurred and led to plant stoppage.
Another factor which seemed to be the cause of underutilisation of dump trucks was the
operator efficiency. To meet the desired 4 cycles per hour for a truck, the average speed
should be 40km/hr, but the average speed of DT41 in 27/08/2012 was only 33.49km/hr. This
decrease in speed however could also be caused by the haul road profile. In some areas the
road was very inclined and trucks’ speed fell to about 9km/hr and prolonged the cycle time.

6.8 CONCLUSIONS
From the results and discussions made in the previous section, the following conclusions
were made concerning the project in hand;
 The bucket size selected was optimal for the required production
 The selected number of trucks (4trucks per excavator) was optimal
 Both excavators and trucks were being underutilised.
 Poor treatment plant performance was the main cause of underutilisation.
 Poor fragmentation (large amount of boulders in the muck pile) was also the cause of
underutilisation.
 Dump trucks capacity (25t) caused underutilisation of excavators under present
circumstances.
 To a small extent, operator efficiency and haul road profile caused underutilisation of
dump trucks.

6.9 RECOMENDATIONS
From the discussions made, the following are recommended for improvement of equipment’s
utilisation;
 There should be a ROM pad near the scalp bin; direct dumping method being used is
not sustainable.
 If possible, the treatment plant should be re-established to include the crushing
system in order to improve its performance.
 The trucks capacity should be increased to at least 30tonnes in order to fully utilize
the excavators.
 The blasting parameters should be reassessed and if possible redesigned to improve
fragmentation.
 High inclinations in the haul roads should be avoided.
 The excavator operators should be rational in finding the right time to sort the
boulders from the muck pile.

CHAPTER 7
GENERAL RESULTS AND DISCUSSIONS
7.1 RESULTS
From MMS analysis;
Fill volume was 16241.51m3
Cut volume was 128100.63m3
Volume of material removed was 111859.12m3
Tonnage of material (M) removed was 224836.83t
The number of trucks recorded by Caspian Tanzania ltd was 8987trucks
Tonnage of material handled in month July (M) as indicated by Caspian was 224675t
ΔM = 161.83t (0.072%)
From excavator data analysis;
Number of cycles per hour if the excavator worked effectively would be 137cycles/hr
The resulting production per hour would be 575.4t and 4603.2t /shift of 8hrs
The utilization of the excavator was 27.78%
From trucks data;
The average cycle time of DT 41 was 30.07min
Max cycles per hour was 2
The optimum cycle time should be 13.48min
The resulting cycles per hour should be at least 4.
The optimal number of trucks/excavator was 4trucks (for Pc- Komatsu excavator) and
3trucks (for Cat 345 excavator).
For blasting data;
Loose volume of blasted material was 26572.73m3
The mass of explosives used was 25916.75kg
The powder factor (PF) used was 0.975kg/m3

34 GENERAL RESULTS AND DISCUSSIONS | © KITALY VENANCE D. (UDOM
2012)
7.2 DISCUSSIONS
The results from production survey done for the month of July were not exactly the same as
the Caspian figures but the deviation was considerably small and acceptable (0.072%). The
survey figures seemed to be bigger than the Caspian figures and this could have been caused
by the following;
 Surveyor limitations; while surveying, the surveyor had to walk around the area to
be surveyed while the rover held in his back was taking measurements of the
positions after every one metre. Some areas were so dangerous to walk along due to
high inclinations and the resulting risk of falling down the slope would cause the
surveyor to walk at a significant distance from the actual/required location. This in
turn resulted into greater volumes of material than it should actually be (see fig
below)
Fig. 7.2: surveyor’s path vs the actual required path (in a section of water trench at NW pit)
 Limitations of the software used; the software used can lead to some discrepancies
due to the very large number of data it has to handle.
The underutilization of the excavator seemed to be caused by poor treatment plant
performance. Plants’ stoppages and/or delays affected much the production of material
handling equipment. For example the plant delays for the month of July were 311.54hrs! This
was equal to 43.3% of the available hours.
Since the dumping method was direct from the pit to the scalp bin of the treatment plant by
trucks, it means that during all these hours the trucks and excavators were idling waiting for
the plant to start working.

35 GENERAL RESULTS AND DISCUSSIONS | © KITALY VENANCE D. (UDOM
2012)
Dump trucks capacities (25t) were also seemed to be the cause of underutilisation of the
excavators. Considering that trucks could make only 4cycles per hour, the maximum 4trucks
per Pc-Komatsu excavator meant that it would have loaded only 400tonnes in an hour whilst
it were supposed to load at least 450tonnes per hour, and the same applies to the Cat 345
excavator. If the dump trucks of at least 30tonnes capacity were used this problem could be
much reduced.
The trucks also seemed to be underutilised (cycle time was long up to more than 30minutes
and the resulting 2cycles per hour) since they spent so long time in queues at dumping and
loading areas. Queuing at dumping place seemed to be caused by poor plant performance
while that at the loading place seemed to be caused by poor fragmentation of the blasted
material.
Blasting seemed to be a bit problematic since some blasts produced too much boulders and
resulted into increased cost of handling the material. This part however seemed to be a little
complicated and required a separate project to see if whether the parameters being used now
(spacing 2.5m and burden 2.5m, type and amount of explosives being used etc) could be
altered to improve the situation.

36 CONCLUSIONS | © KITALY VENANCE D. (UDOM 2012)
CONCLUSIONS
Following the observations and the discussions put forward in the previous section the
following conclusions can be made;
 Production surveys were a very good approach to estimate the monthly production for
Caspian payment issuing.
 Material hauling equipment were being underutilised
 Poor plant performance and poor fragmentation together with the small capacity of
the dump trucks were the primary causes of underutilisation.
 Blasting operations needed to be reassessed and if possible altered to reduce boulder
production.

37 RECOMMENDATIONS | © KITALY VENANCE D. (UDOM 2012)
RECOMMENDATIONS
From the observations and discussions made, the following were recommended to WDL;
 The treatment plant should be re-established to include crushing system in order to
recover some diamonds that may be included in the kimberlitic boulders being thrown
away, and reduce blasting and material handling costs.
 If the present plant should keep on working, a detailed study (project) on blasting
parameters should be done to improve fragmentation in pit.
 In case there is any improvement on the plants’ performance, the company (Caspian)
should see the possibility of using trucks with bigger capacity (at least 30tonnes) to
ensure full utilisation of their excavators.
 There should be a ROM pad for sustainable production of both plant and material
handling equipment.
 For production surveys, the surveyor should walk as close as possible to the actual
boundary of the surveyed area to provide accurate results.

38 NOMENCLATURE | © KITALY VENANCE D. (UDOM 2012)
NOMENCLATURE
∑ - Summation of
ANFO – Ammonium Nitrate + Fuel Oil
BF – Bucket fill factor
DH – Drill Hole
DT – Dump Truck
DTH – Down The Hole
DTM – Digital Terrain Model
FEL – Front End Loader
GPS – Global Positioning System
MMS – Model Maker System
NW – North West
PETN - Pentaerythritol tetranitrate
PF – Powder factor
ROM – Run Off Mine
SW – South West
TGO – Trimble Geostatistics Office
TNT - Trinitrotoluene
Vbcm – Bulk volume of material
Vlcm – Loose volume of material
WDL – Williamson Diamonds Limited
Δ – Change in
ρbcm – Bulk density of material
ρlcm – Loose density of material
ρm – Average density of material

39 REFFERENCES | © KITALY VENANCE D. (UDOM 2012)
REFFERENCES
"Productivity Considerations for Shovels and Excavators"; Steve Fiscor; Engineering and
Mining Journal, Sep 2007
Howard L. Hartman et al, SME Mining Engineering Hand Book (second edition volume
1) (1992), Society of Mining Metallurgy and Exploration Inc, Litlleton Colorado
http://material.eng.usm.my/stafhome/termizi/EBS419E%20Blasting%20Tech/H_BLASTIN
G%20IN%20SURFACE%20EXCAVATION.pdf
http://www.arl.army.mil/arlreports/2007/ARL-TN-0281.pdf
http://www.assakkaf.com/courses/ence420/lectures/chapter13.pdf
http://www.austinpowder.com/BlastersGuide/docs/0-
%20Complete%20Blasters%20Guide.pdf
http://www.dynonobel.com/files/2010/04/1062-Bulk-Emulsions-Explosives-09-16-10.pdf
http://www.ehow.com/how_to_alculate_excavator_bucket_capacity
http://www.intdetsymp.org/detsymp2002/papersubmit/finalmanuscript/pdf/hirosaki-149.pdf
http://www.rocscience.com/library/rocnews/april2002/GolderArticle.pdf
The University of Dodoma, MN 301 (Mine Transportation) course lectures notes, by Eng S.
Lupyana
The University of Dodoma, MN 302 (Surface Mining Methods) course lecture notes, by Eng.
Karim Baruti

40 APPENDICES | © KITALY VENANCE D. (UDOM 2012)
APPENDICES
Appendix 1: Production Survey data and analysis
Table 12.1: Part of the production survey data for the month of July
Point Eastings(m) Northings(m) Elevation(m)
bs1 5855.025 5431.042 1206.858
wd77 6033.16 5399.48 1206.042
wd57 5698.34 6596.44 1206.01
be-d 7003.543 6048.169 1211.881
Af 6033.158 5399.462 1206.042
Bf 5698.354 6596.447 1206.01
Cf 7003.532 6048.181 1211.906
tail1 6112.445 4745.381 1257.6
j1 5840.783 6178.853 1139.628
j2 5841.571 6179.439 1139.671
j3 5842.361 6179.677 1139.686
j4 5843.304 6179.624 1139.574
j5 5844.074 6179.321 1139.586
j6 5844.711 6178.478 1139.576
j7 5844.965 6177.438 1139.549
j8 5845.116 6176.789 1139.684
j9 5845.021 6175.69 1139.617
j10 5844.854 6174.652 1139.758
j11 5844.886 6173.466 1139.728
j12 5844.815 6172.256 1139.698
j13 5844.644 6171.031 1139.734
j14 5844.332 6169.826 1139.767
j15 5844.132 6168.582 1139.764
j16 5844.013 6167.11 1139.773
j17 5843.458 6165.127 1139.786
j18 5843.105 6164.095 1139.742
j19 5842.924 6162.996 1139.616
j20 5842.759 6161.947 1139.63
j21 5842.396 6160.714 1139.505
j22 5842.241 6159.45 1139.497
j23 5842.117 6158.339 1139.405
j24 5842.07 6157.168 1139.429
j25 5842.16 6156.038 1139.311
j26 5842.246 6155.082 1139.401
j27 5842.202 6154.094 1139.355
j28 5841.904 6153.09 1139.35

Fig. 12.1(a): Worked out areas for the month of July (modelled by the aid of model maker
system software)
Fig. 12.1(b): The Mwadui pit DTM

From MMS computations,
Cut volume (Vc) = 128100.63m3
Fill volume = (Vf) = 16241.51m3
Volume of material removed (V) = Vc - Vf
V = 111859.12m3
Tonnage of material removed (M) = V*ρm
Where ρm is average density of material (ρm = 2.01t/m3
)
M = 111859.12m3
*2.01t/m3
M = 224836.83t
The number of trucks recorded by Caspian Tanzania ltd was 8987trucks
The truck factor was 25tonnes
Tonnage of material handled in month July (M) as indicated by Caspian
M = 8987 * 25
M = 224675t
Deviation from survey results (ΔM) = 224836.83- 224675
ΔM = 161.83t (0.072%)

Appendix 2: Loading equipments performances
Table 12.2: Excavator (Pc-Komatsu) operations at SW Block C (03/08/2012)
Cycle time (s) Number of
cycles/passes
Idle time (s)
26.37 8 49.90
28.16 5 320.32
30.20 6 70.47
25.86 5 429.48
25.90 6 2736.50
25.13 6 600.40
28.41 7 85.62
29.85 6 60.15
25.25 8 3600.25
23.68 5 240.18
28.08 6 620.88
23.84 6 325.95
25.11 6 540.89
25.65 6 1200.23
26.40 7 75.82
27.15 7 60.71
25.45 8 425.63
25.80 6 900.28
25.15 6 480.80
25.60 5 27.54
25.76 7
26.19 6
27.15 6
27.62 8
25.58 7
26.19 6
25.37 6
26.95 5
27.00 6
28.21 8
25.12
25.63
25.71
25.61
25.62
26.88
Total 947.63 190 12852
Average 26.3231

Computations
Number of cycles per hour (Cph)
Cph = 3600s/Average cycle time (Ctav)
Where Ctav = 26.3231s/cycle
Cph = 3600 / 26.3231
= 137cycles/hr
Production per cycle (Pcy)
Pcy = Bucket fill factor (BF) * Bucket capacity (C)
Where C = 2m3
, BF = 1.05
Pcy = 2*1.05 = 2.1m3
(=4.2tonnes since density of material is 2t/m3
)
Pcy = 4.2t
Production per hour (Phr)
Phr = Pcy * Cph
Phr = 4.2 *137
=575.4t
The required production per hour was 520tonnes, thus the bucket capacity selected
(2m3
) was optimal.
Production per shift (Psh)
Psh = Phr * Number of hours per shift
Psh = 575* 8hrs
=4603.2t

Appendix 3: Haulage equipments performances
Table 12.3(a): Dump Trucks statistics (06/08/2012, NW Block B to Scalp Bin)
Dump
truck
Queuing time
(min)
Manoeuvring
time (min)
Loading time
(min)
Travelling to & from scalp
bin + dumping and queuing
time at the scalp bin (min)
DT18 0.00 1.03 3.25 37.00
DT19 0.00 1.00 3.06 33.94
DT21 0.00 0.80 3.05 31.40
DT23 0.00 1.05 3.98 26.97
DT41 0.00 0.82 3.04 17.98
DT18 0.33 0.65 3.02 32.08
DT19 0.14 0.77 3.09 13.00
DT21 3.02 0.50 3.48 27.54
DT23 2.38 0.54 3.08 12.00
DT41 5.93 0.82 3.25 23.00
Table 12.3(b): Detailed study on DT 41 at NW Block C (27/08/2012, 9a.m to 4p.m)
Queue
(at
loading
place)
(min)
Manoeu
vring (at
loading
place)
(min)
Load
time
(min)
Travel
time
(loaded
) (min)
Queue
(at
dumpi
ng
area)
(min)
Manoeu
vring
(at
dumpin
g place)
(min)
Dump
time
(min)
Travel
time
(empty)
(min)
Cycle
time
(min)
0 0.64 3.71 6.25 27.25 0.6 0.7 5.33 44.48
1.48 0.73 3.65 5.67 0 0.5 0.83 6 18.86
10 0.83 4.9 6.52 1.42 0.8 1.03 5.17 30.67
2.75 0.92 3.08 5.17 0 0.65 1.02 5.42 19.01
7.67 0.83 3.45 5.55 0 0.63 0.9 3.82 22.85
16.18 1.07 3.07 5.78 19.98 0.83 0.92 4.03 51.86
0.97 0.65 3.1 5.03 0 0.47 1.17 3.92 15.31
3.95 1.72 2.77 5.81 15.83 0.87 1.03 4.77 36.75
1.08 0.92 2.03 5.3 35.25 0.92 1.02 3.62 50.14
2.7 0.5 2.42 3.95 0 0.97 1.02 3.9 15.46
33.59 0.65 2.83 5.47 0 0.7 0.83 3.92 47.99
2.85 0.7 2.65 5.85 0 0.98 0.47 3.75 17.25
3.67 0.82 2.74 5.48 0 0.86 1.02 3.83 18.42
2.05 0.78 2.92 5.04 15.92 0.67 1 3.59 31.97

Computations
Cycle times (Queuing time + Manoeuvring time + loading time + travelling, dumping and
queuing time at the scalp bin/damp area) for generalized data (table 12.3(a)) can be obtained
as follows
DT 18
 First trip 1.03+3.25+37 = 41.28min
 Second trip 0.33+0.65+3.02+32.08 = 36.08min
DT 19
 First trip 1+3.06+33.94 = 38min
 Second trip 0.14+0.77+3.09+13.00 = 17min
DT 21
 First trip 0.80+3.05+31.40 = 35.25min
 Second trip 3.02+0.50+3.48+27.54 = 34.54min
DT 23
 First trip 1.05+3.98+26.97 = 32min
 Second trip 2.38+0.54+3.08+12.00 = 18min
DT 41
 First trip 0.82+3.04+17.98 = 21.84min
 Second trip 5.93+0.82+3.25+23.00 = 33min
Max cycles per hour was 2
More data
The haulage distance was 2.75km (from both NW Block B and NW Block C to scalp bin)
The maximum allowable speed in pit was 40km/hr
The average loading time (Pc-Komatsu excavator) was 3.23min and 4.3min (for Cat 345)
The manoeuvring + dumping time was 2min

From the above data, cycle time should actually be as follows;
Time (to and from the scalp bin) = (2(2.75)/40)*60min
=8.25min
Cycle time = 8.25+2+3.23
= 13.48min
From this, the number of cycles per hour should be at least 4.
Again, from the travel time obtained;
The number of trucks per excavator (T) can be obtained as
T = ((Travel + manoeuvring + dumping time)/Loading time) +1
T = ((8.25+2)/3.23)+1
T = 4.17 ≈ 4trucks (for Pc- Komatsu excavator)
The same procedure gives 3trucks (for Cat 345 excavator)
From table 12.3(b);
The average cycle time of DT 41 = ∑cycle time/Number of cycles
= 30.07min
If the queuing time at dumping area were removed;
The average cycle time would be 21.81min
Again, with the excessive queuing time at the loading place removed (taking 1min as the
maximum allowable);
The average cycle time would drop to 16.39min
Also from table 12.3(b);
Average travel time (loaded) = ∑Travel time (loaded)/Number of cycles
= 5.49min
Average travel time (empty) = ∑Travel time (empty)/Number of cycles
= 4.36min

The average travel time = (5.49+4.36)/2 = 4.93min
Average speed (Ve) = total distance/total time
Total distance was 77km (14 cycles * 2(distance from load to scalp bin))
Total travel time was 137.94min
Ve = 77/137.94 = 0.5582137*60
Ve = 33.49km/hr
Fig. 12.3(a): Time distribution for individual Fig. 12.3(b): Time distribution for
cycles for DT41 individual cycles (excessive
queuing time removed)
0
10
20
30
40
50
60
1 3 5 7 9 11 13
timedistribution(min)
cycle
Travel time
(empty) (min)
Dump time
(min)
Manoeuvring
(at dumping
place) (min)
Queue (at
dumping area)
(min)
Travel time
(loaded) (min)
Load time
(min)
Manoeuvring
(at loading
place) (min)
0
5
10
15
20
25
1 3 5 7 9 1113
timedistribution(min)
cycle
Travel time
(empty) (min)
Dump time
(min)
Manoeuvring
(at dumping
place) (min)
Travel time
(loaded) (min)
Load time
(min)
Manoeuvring
(at loading
place) (min)
Queue (at
loading place)
(min)

Appendix 4: Excavator utilization computations
Total actual operating time (Tto)
Tto = Average cycle time (Ctav) * Number of cycles (N)
Where N = 190cycles and
Ctav = 26.3231s/cycle (from table 12.2)
Tto = 190 * 26.3231
= 5001.40s
Total idle time (Tti)
Tti = 12852s
The excavator was available for 5hrs (18000s), and the shift was 8hrs (28800s)
Availability (A)
A = (5/8) *100%
= 62.5%
Utilization (U)
U = (Tto /Available time) * 100%
U = (5001.40/18000) *100%
= 27.78%

Appendix 5: Drilling observations
Table 12.5: Drilling statistics at NW Block C
Drill
Hole
Drilling
time
(min)
Drill rod
change
time
(min)
Time to
remove the
bit from the
hole (min)
Time to move
and set the
boom in a new
drill hole (min)
Delaying
time
(min)
Remarks
DH1 2.75
2.01
0.82
1.08
0.58
- Kimberlitic
chips
DH2 3.72
1.27
0.65
0.98
1.70
-
DH3 4.38
0.55
2.13
0.53
0.95
0.75
1.00
1.83
1.00
Receiving
instructions
Bit stuck in
the hole
No reason
DH4 3.00
2.42
1.17
0.88
1.2
-
DH5
3.17
1.83
0.52
0.92
1.4
0.31 No reason
DH6 12.63
1.55
5.03
1.63
0.93
1.38
1.00
White dust
Kimberlitic
chips
White dust
Changing bit

Appendix 6: Blasting statistics
Explosives
 Emulsion explosive (ρe = 1.25t/m3
)
 Boosters (305 boosters @ 150g)
 Non electrical detonators (305 two sided detonators, @ 500ms delay into the hole and
42ms delay protruding on the surface)
 Delays (123delays @ 42ms)
 Detonating cord (2m)
 Electrical detonator (1 detonator)
Blast holes
 Number of holes (N) = 305
 Average hole depth (H) = 7.9m
 Holes’ diameter (D)= 102mm
 Charge length (Lch) = 6m
Blast area (SW Block C)
 Length = 148m
 Width = 20m
 Rock type is clayish
 Density of material insitu (ρbcm) = 2.27t/m3
 Density of material loose (ρlcm) = 2.00 t/m3
Initiation system
 Combined (electrical and non-electrical) detonating system
Computations
Insitu volume (Vbcm) = 148*20*7.9
Vbcm = 23384m3
Swell Factor (SF) = ρlcm/ ρbcm = 2.00/2.27
SF = 0.88
Loose volume (Vlcm) = Vbcm/SF = 23384/0.88
Vlcm = 26572.73m3

52 | © KITALY VENANCE D. (UDOM 2012)
Mass of emulsion used (Me) = Lch *(πD2
/4) * ρe *N = 6*((π (0.102)2
)/4)*1.25*305
Me = 25.87tonnes (25871kg)
Mass of boosters used (Mb) = 305*150/1000
Mb = 45kg
Mass of explosives used (M) = 25871+45
M = 25916.75kg
Powder factor (PF) = M/ Vlcm = 25916.75kg/26572.73m3
PF = 0.975kg/m3

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