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ODZI RIVER TO MINE CONCESSION B PROCESS
WATERSUPPLY PUMPING AND PIPELINE DESIGN
AND CONSTRUCTION PROJECT
COMPILED BY:
Augustine Marume
Patrick Magwegwe
Jacqueline Madziva
July 2013
Page 2
EXECUTIVE SUMMARY
Marange Resources (Pvt) Ltd, is a wholly government of Zimbabwe owned entity through the
Zimbabwe Mining Development Corporation (ZMDC), mining and processing diamonds in
the Chiadzwa diamond field in Manicaland Province. The mine concessions are situated
20km from the processing plants, which are located close to the Odzi River for easy
accessibility of water which is a critical raw material for diamond processing. The current
low performance in production due to aging mobile equipment which is perennially on
breakdowns has necessitated the need to relocate the processing plants to the mine
concessions close to the ore bodies. This change in facilities set-up requires that, water being
a critical resource in diamond processing must be continuously available for the plants to
operate consistently and sustainably with minimum stoppages.
The authors were tasked to design a water supply system from the Odzi River to the
Concession B processing plants. The project involved pumps sizing, pipeline dimension and
material of construction recommendation as well as design of the two intermediate water
reservoirs along the pipeline.
From the values of cost and adequate pump-sizing recommendations, the most appropriate
pipe size option was 10 inches. The 12 inch pipe is the most expensive of the three, the 8 inch
pipeline is less expensive than the 10 inch but from the pump selection calculations the pump
that is compatible with the total head for the 8 inch pipe (93m where pump head from the
KSB pump selection charts for a flow rate of 100 000l/hr was 91m).
Due to lower cost considerations and material characteristics, out of the three materials under
consideration the most desirable were asbestos-cement and high density polyethylene
(HDPE). Asbestos-cement has better characteristics compared to HDPE that is durability and
its resistance to acid and salt corrosion. Fire resistance was also a major attractive quality
upon selection where asbestos-cement had a high fire resistance compared to high density
poly ethylene which is weak in fire resistance. Implementing the use of High Density
Polyethylene as the material of construction for the pipelines would result in lower
maintenance and purchasing costs.
From pump selection calculations the suitable pump for the pump station 1 at Odzi River, is
the KSB ETANORM 80-400. Similar pumps were selected for the first and second stations
since the 2nd pump and the 3rd pump will be in series thus there is need for the same pump to
Page 3
avoid pumps cavitation as well as operational design issues. The KSB ETANORM-R 125-
400.R is the most suitable pump for the 2nd and 3rd pump station.
Three options for pipeline material where considered, that using asbestos-cement, high
density polyethylene or steel. The total cost of installing a 15,6km long pipeline from Odzi
River to Concession B of 10 inch diameter, using asbestos-cement as the material of
construction amount to a value of US $1,838,785.00
The total cost of installing a 15,6km long pipeline from Odzi River to Concession B of 10
inch diameter, using high density polyethylene as the material of construction amount to a
value of US $1,721,425.00
The total cost of installing a 15,6km long pipeline from Odzi River to Concession B of 10
inch diameter, using steel as the material of construction amount to a value of
US $3,140,221.00
Page 4
Introduction .................................................................................................................................................................................................................. 7
General Objectives ....................................................................................................................................................................................................... 7
Specific Objectives ...................................................................................................................................................................................................... 7
Problem Statement ....................................................................................................................................................................................................... 7
Background .................................................................................................................................................................................................................. 7
Justification .................................................................................................................................................................................................................. 7
Proposed design specifications and calculations ......................................................................................................................................................... 8
Costing ....................................................................................................................................................................................................................... 18
TOTAL COST OF THE WATER SUPPLY SYSTEM PROJECT........................................................................................................................... 22
Recommendations ...................................................................................................................................................................................................... 24
References .................................................................................................................................................................................................................. 24
Page 6
ODZI RIVER
Introduction This report serves to show all calculations and considerations carried out by the authors as
well as consultations with other technical people in the organisation.
General Objectives To design an adequate water supply system from Odzi river to Concession B
Specific Objectives 1. To size a pump that will efficiently pump water from Odzi river to an intermediate
pump station below Ushonje mountain
2. To specify accurate pipe line size and material of construction
3. To analyse all possible routes for pipe line layout and determine the best
4. To size pumps that will pump water at the intermediate pump station up the Ushonje
Mountain to the Water Tank
Problem Statement Due to the inadequacy of water at the Concession B there is need to design an efficient water
supply for efficient processing of ore.
Background Initially a pond was constructed at the Concession B to supply water for the Power screen 4
harvesting water from the rains, this pond was supplemented by a 5000l per hour borehole.
An elutriation and a wet feed preparation plants were later added to the facilities in
concession B to increase the diamond ore tonnage required by the dense media separator
(DMS) plants hence the increase in water uptake. The new set-up plants required 20,000l per
hour of water which was coming from the 5000l/hr capacity borehole supplemented by a 30
000l capacity bowser ferrying water from Odzi River which was 20km away.
Justification The major problem being faced at the Concession B is inadequacy of water.
The main water supply has proved to be inadequate to sustain all processing operations. This
is mainly due to lack of an adequate and continuous water supply system. In an effort to
improve the water situation, the water bowser has been utilised to supply water at the
concession B processing plant. The bowser with a carrying capacity of 30 000l can only
manage to supply 90 000l per shift which translates to 11 250l/hr. Current water requirements
at the processing plant amount to 20 000l/hr hence combining the water supply rate from both
the 5 000l/hr borehole and water bowser, report a deficiency in the water circuit.
Page 8
The bowser water supply system is very costly as it consumes 336litres of fuel in a day which
amounts to $13 104 in a month hence $157 248 per annum. To efficiently supply the
processing plant, two bowsers would be required the operating cost of which would amount
to $26 208 a month. This cost added to accruing costs incurred upon depreciation of the
vehicle may prove to be very costly for the organisation.
Plans are currently underway to relocate the 65tph Dense Medium Separator (DMS) unit to
the Concession B processing plant which will increase water consumption rate to a value of
around 100 000l/hr. This has been proven to be a beneficial move as transportation of ore
from the concession to the processing plant is highly costly as it amounts to $111 930 per
month in terms of fuel costs for haulage equipment excluding depreciation of the vehicles. To
cheaply and sufficiently sustain water requirements at the concession B processing plant it
would be necessary to construct a pipeline.
Proposed design specifications and calculations
Assumptions
Fluid velocity is constant throughout the system (steady state flow)
Negligible flow resistance on bends
Negligible differential pressures across individual components and flow rates or
velocities within a pipeline.
Pipeline design:
The main aspects of consideration for pipeline design are size, material of construction and
cost. Calculations on similar material pipes ranging from 4-12 inches were devised.
Given data:
Flow rate 100 000l/hr (440gpm)
Pipe size range 4 inches-12 inches
Relative pipe roughness:
Page 9
HDPE 0.009
Asbestos-Cement 0.011
Steel 0.012
1. Calculating friction factors for all material for pipe sizes (4-12inches):
Where Reynold’s number, Re
Reynolds’s number:
Where is density of water
u is fluid velocity
d is the pipe diameter
v is the kinematic viscosity of water
PIPE SIZE(INCHES) REYNOLDS
NUMBER(×
4 3.47
6 2.30
8 1.73
10 1.39
12 1.14
Where velocity of flow
Where v is the velocity of flow in feet per second
Q is the flow rate in gallons per minute
Page 10
D is the pipe diameter in inches
Pipe Diameter(inch) Velocity Flow(ft/s)
4 11.24
6 4.99
8 2.81
10 1.80
12 1.25
Friction head
where K is the relative pipe roughness
D is the pipe diameter in metres
Re is the Reynolds number
Using the formulae for Reynolds number and friction factor at different pipe diameter and
velocity, the following values of friction factor values were obtained:
Table of friction factor values
TYPE OF MATERIAL
PIPE
SIZE(inches)
ASBESTOS
CEMENT
HDPE STEEL
4 0.10640 0.09528 0.11183
6 0.08570 0.0776 0.08961
8 0.07453 0.0679 0.07768
10 0.06734 0.0617 0.07003
12 0.06269 0.0576 0.06509
Page 11
2. Sizing pump 1
Calculating friction head, Hf
Where Hf is the friction head in feet
f is the friction factor
L is the pipe length in feet
D is the pipe diameter in inches
v is the velocity flow in ft/s
g is the gravitational force in ft/s2
TYPE OF
PIPE
PIPE SIZE FLUID
VELOCITY
FRICTION
FACTOR
FRICTION
HEAD(metres)
Asbestos 4 11.24 0.1064 346.90
6 4.99 0.0857 36.71
8 2.81 0.0745 7.59
10 1.80 0.0673 2.25
12 1.25 0.0627 0.84
Steel 4 11.24 0.1118 385.99
6 4.99 0.0896 38.39
8 2.81 0.0777 7.91
10 1.80 0.07003 2.34
12 1.25 0.06509 0.88
HDPE 4 11.24 0.09528 310.65
Page 12
6 4.99 0.0776 33.24
8 2.81 0.0679 6.92
10 1.80 0.0617 2.06
12 1.25 0.0576 0.77
Calculating total head, Htotal
Htotal = Hstatic + Hf
Where, Hstatic – static head (metres)
Hf – frictional head (metres)
For a static head of 65m,the following values of total head were obtained:
TYPE OF PIPE PIPE SIZE FRICTION
HEAD(m)
TOTAL HEAD(m)
Asbestos 4 346.90 411.90
6 36.71 101.71
8 7.59 72.59
10 2.25 67.25
12 0.84 65.84
Steel 4 348.37 413.37
6 38.39 103.39
8 7.91 72.91
10 2.34 67.34
12 0.88 65.88
HDPE 4 310.65 375.65
6 33.24 98.24
8 6.92 71.92
10 2.06 67.06
12 0.77 65.77
Page 13
Isolating values for a flow rate of 100 000l/hr = 440g/m and using these to obtain accurate
pipe sizes from the KSB pipe selection charts attached, two sizes of centrifugal pumps may
be considered:
For an 8, 10 or 12 inch pipeline;
ETANORM 80-400 pump speed (n) =1750 rpm or
ETANORM 125-500.2R n=1450 rpm
3. Sizing pump 2
Where Hf is the friction head in feet
f is the friction factor
L - the pipe length in feet
D is the pipe diameter in inches
v is the velocity flow in ft/s
g is the gravitational force in ft/s2
For a pipe length of 3.25km, acceleration due to gravity=32.2ft/s2, the following values of
frictional head where obtained using the equation above
TYPE OF
PIPE
PIPE SIZE FLUID
VELOCITY
FRICTION
FACTOR
FRICTION
HEAD(metres)
Asbestos 4 11.24 0.1064 169.61
6 4.99 0.0857 17.95
8 2.81 0.0745 3.71
10 1.80 0.0673 1.10
12 1.25 0.0627 0.41
Page 14
Steel 4 11.24 0.1118 178.26
6 4.99 0.0896 18.77
8 2.81 0.0777 3.87
10 1.80 0.07003 1.14
12 1.25 0.06509 0.43
HDPE 4 11.24 0.09528 151.88
6 4.99 0.0776 16.25
8 2.81 0.0679 3.39
10 1.80 0.0617 1.01
12 1.25 0.0576 0.38
For a static head of 90m the total head values obtained were:
PIPE TYPE Pipe size(inches) Friction
head(metres)
Total head(metres)
Asbestos 4 346.90 259.61
6 36.71 107.95
8 7.59 93.71
10 2.25 91.1
12 0.84 90.41
Steel 4 348.37 268.26
6 38.39 108.77
8 7.91 93.87
10 2.34 91.14
12 0.88 90.43
HDPE 4 310.65 241.88
6 33.24 106.25
8 6.92 93.39
10 2.06 91.01
12 0.77 90.38
Page 15
Isolating values for flow rate of 100 000l/hr = 440g/m and using these to obtain accurate pipe
sizes from the KSB pipe selection charts attached, two sizes of centrifugal pumps may be
considered:
For an 8 inch pipeline;
ETANORM 125-500.2R n=1450 rpm
For a 10 or 12 inch pipeline;
ETANORM 125-400 n=1750 rpm
Sizing pump 3
Where Hf is the friction head in feet
f is the friction factor
L is the pipe length in feet
D is the pipe diameter in inches
v is the velocity flow in ft/s
g is the gravitational force in ft/s2
For a pipe length of 1km, acceleration due to gravity=32.2ft/s2, the following values of
frictional head where obtained using the equation above
TYPE OF
PIPE
PIPE SIZE FLUID
VELOCITY
FRICTION
FACTOR
FRICTION
HEAD(metres)
Asbestos 4 11.24 0.1064 52.2
6 4.99 0.0857 5.54
Page 16
8 2.81 0.0745 1.14
10 1.80 0.0673 0.34
12 1.25 0.0627 0.13
Steel 4 11.24 0.1118 54.86
6 4.99 0.0896 5.83
8 2.81 0.0777 1.19
10 1.80 0.07003 0.35
12 1.25 0.06509 0.13
HDPE 4 11.24 0.09528 31.16
6 4.99 0.0776 5.01
8 2.81 0.0679 1.04
10 1.80 0.0617 0.31
12 1.25 0.0576 0.12
For a static head of 90m the total head values are:
TYPE OF SIZE PIPE SIZE
(inches)
FRICTION HEAD
(metres)
TOTAL HEAD
(metres)
Asbestos 4 346.90 142.2
6 36.71 95.54
8 7.59 91.14
10 2.25 90.34
12 0.84 90.13
Steel 4 348.37 144.86
6 38.39 95.83
8 7.91 91.19
10 2.34 90.35
12 0.88 90.13
HDPE 4 310.65 121.16
6 33.24 95.01
8 6.92 91.04
Page 17
10 2.06 90.31
12 0.77 90.12
Isolating values for flow rate (100 000l/hr = 440g/m) and using these to obtain accurate pipe
sizes from the KSB pipe selection charts attached, three sizes of centrifugal pumps may be
considered:
For a 6,8,10 or 12 inch pipeline;
ETA 80-250 pump speed (n) =2900 rpm or
ETANORM 80-200 n=3500 rpm
For a 8,10 or 12 inch pipeline;
ETANORM 125-400 n=1750 rpm
PIPELINE MATERIAL SELECTION
Three materials for pipelines were considered for sizes, 8- 12 inches, these are steel, HDPE
and Asbestos-Cement. Upon selection of the most appropriate material the following
characteristics were put into consideration.
Carrying capacity.
Durability.
Fire resistance
Maintenance cost.
Type of water to be conveyed
MATERIAL OF CONSTRUCTION
CHARACTERISTICS ASBESTOS-
CEMENT
STEEL HDPE
Carrying capacity.
Sizes are 100mm to
600mm diameter(18
inches)
diameter no greater
than 16 inches
Only available
350mm(12 inches)
diameter
Durability. Average life Less durable where
effects of corrosion
Expected life
Page 18
is 30 years.
may be considered is 25 years.
Corrosion resistance
Immune to actions
of acids, salts, soil
and corrosion
Require coating to
minimise effects of
corrosion
High corrosion
resistance
Maintenance cost.
Less plumbing cost
due to less friction
High maintenance
charges are required.
Easy to handle.
Type of fluid to be
conveyed
Water Oil/petroleum and in
some instances raw
water
Water
In terms of capacity, type of fluid conveyed all three materials of construction could be
considered as appropriate. However, asbestos-cement and High Density Polyethylene may be
regarded as the most appropriate material of construction due to their low costs and
favourable characteristics.
Costing
1. Cost of pipeline
One of the most significant considerations for material selection was cost of purchasing the
material for the 15,6km pipeline.
MATERIAL OF CONSTRUCTION COST IN US$
PIPE SIZE(Inches) ASBESTOS-
CEMENT
STEEL HDPE
8 1,136,070.00 1,783,834.00 1,096,524.00
10 1,526,070.00 2,709,200.00 1,419,379.00
12 2,221,284.00 3,773,403.00 2,188,589.00
In terms of cost considerations, HDPE is the most favourable, however its low fire resistance
is a tremendous disadvantage when considering location of the pipeline as this may be prone
Page 19
to veld fires etc. Asbestos-cement would thus be the second best option to consider in terms
of cost.
The cheapest pipe size to consider for a flow rate of 100 000l/hr would be 10 inches as an 8
inch pipeline would be ‘nailing the hammer plate’ with pump size considerations.
2. Pump cost
PUMP TYPE(all KSB) PUMP SPEED (rpm) COST IN US ($)
Etanorm 125 - 400 1750 9,318.00
Etanorm 80-400 1750 3,184.00
Etanorm 125 – 500.2R 1450 6,971.00
3. Cost of valves and fittings
VALVE TYPE COST OF PROJECT REQUIREMENT
IN US($)
Non-return foot valve x 1 1,200.00
Non return valve x 5 2,848.00
Butterfly valve x 4 2,280.00
TOTAL COST 6,328.00
4. Tanks construction cost
Tank capacity (Litres) Brick Requirements cost in
USD
Cement Requirements cost
in USD($)
200,000 2,276.00 375.00
5,000,000 11,322.00 750.00
TOTAL 13,598.00 1,125.00
Page 20
5. Equipment cost
EQUIPMENT PERIOD EXPECTED
FOR HIRE
TOTAL HIRING COST IN
USD ($)
Excavator 3 days 3,360.00
Dozer 3 days 3,360.00
Crane 1 month 24,000.00
TLB 1 week 5,600.00
TOTAL COST IN USD 36,320.00
6. Labour
Boilermakers x 5 (each @ $1,300 per month) $6,500.00
Boilermaker assistant x10 (each @ $800 per month) $8,000.00
Fitter and turner x 2 (each @ $1300 per month) $2,600.00
Fitter and turner assistants x 2 (each @ 800 per month) $1,600.00
Electrician x 1 (each @ $1,300 per month) $1,300.00
Electrician assistant x 1(each @ $800 per month) $ 800.00
Builder x 1(each @ $1,300 per month) $1,300.00
Builder assistant x 1(each @ $800 per month) $ 800.00
Total $22,900.00
7. Power requirements
Calculating the power required by the pumps:
Epump =
Where,
Epump – Pump efficiency
Page 21
Water horsepower (WHP) - the theoretical power needed for pumping water (kW)
Brake horsepower (BHP) - the input power needed at the pump shaft (kW)
WHP =
Where Q is the flow rate in litres per second
H is the total head in metres
BHP =
Given pump efficiency for KSB pumps is 76% from system curves,
Therefore for a flow rate of 100 000l/s and head of 65 and 90m, the following values for
brake horsepower were obtained:
PUMP BHP
REQUIREMENTS
SIZE OF GENERATOR TO
BE UTILISED
ETANORM 80-400 23 kW 38 kVA
ETANORM 125 – 400.R 32.1 6kW 50 kVA
The 1st pump station may utilise power from the Zimbabwe Electricity Supply Authority
(ZESA). However, the second and third pumps would require an external power supply
where generators may be used for this purpose.
PUMP STATION GENERATOR POWER
DRAW
COST IN USD($)
2 50 kW 21,728.00
3 50 kW 21,728.00
TOTAL COST US ($) 43,456.00
Page 22
TOTAL COST OF THE WATER SUPPLY SYSTEM PROJECT
Option 1 (Asbestos-Cement Pipeline):
Asbestos-cement has better characteristics compared to HDPE that is durability and its
resistance to acid and salt corrosion. Fire resistance was also a major attractive quality upon
selection where asbestos-cement had a high fire resistance compared to high density poly
ethylene which is weak in fire resistance.
Pipeline $1,526,070.00
Valves $ 6,328.00
Equipment cost $ 36,320.00
pumps $ 21,820.00
power $ 43,456.00
Tanks $ 14,723.00
Labour $ 22,900.00
Contingency allowance $ 167,162.00
GRAND TOTAL $1,838,785.00
Converting the amount in production terms where 1 carat = $50, the total cost of constructing
the water supply system using Asbestos-cement as the material of construction for the
pipeline is 36,775 carats.
Option 2 (High Density Polyethylene Pipeline):
The second option would be implementing the use of High Density Polyethylene as the
material of construction for the pipelines.
High Density Polyethylene has lower maintenance and purchasing costs than Asbestos-
cement in spite of asbestos-cement’s high durability.
HDPE pipeline $1,419,379.00
Valves $ 6,328.00
Equipment cost $ 36,320.00
Page 23
power $ 43,456.00
pumps $ 21,820.00
Tanks $ 14,723.00
Labour $ 22,900.00
Contingency allowance $ 156,493.00
GRAND TOTAL $1,721,425.00
Converting the amount in production terms where 1 carat = $50, the total cost of constructing
the water supply system using is HDPE as the material of construction for the high density
polyethylene pipeline is 34,428 carats.
Option 3 (Steel Pipeline):
The third option would be to implement the use of steel as the material of construction for the
pipeline. Steel however, is less durable than asbestos-cement and may require coating to
minimise effects of corrosion. Steel is also very expensive upon purchasing and high
maintenance costs may be incurred.
Steel pipeline $2,709,200.00
Valves $ 6,328.00
Equipment cost $ 36,320.00
power $ 43,456.00
pumps $ 21,820.00
Tanks $ 14,723.00
Labour $ 22,900.00
Contingency allowance $ 285,474.00
GRAND TOTAL $3,140,221.00
Converting the amount in production terms where 1 carat = $50, the total cost of constructing
the water supply system using steel as the material of construction for the pipeline is:
62,804 carats.
Page 24
Recommendations The most suitable design would be that of constructing a 15,6km asbestos-cement pipeline
with three pump stations.
Asbestos-cement has a high durability (average life of 30years) thus, it is a long-term
investment. Its high corrosion resistance and fire resistance also make it highly favourable
particularly where the pipeline may be exposed to veld fires and vandalism. Less friction in
asbestos-cement pipes also results in less pumping costs. Costs of purchasing an asbestos-
cement pipeline are quite affordable as they are much cheaper than those of purchasing a
steel pipeline and slightly higher than high density polyethylene.
The 1st pump station will utilise a KSB ETANORM 80-400 centrifugal pump while the 2nd
and 3rd pump stations will utilise KSB ETANORM 125 – 400.R centrifugal pumps. The
pipeline will be fitted with water taps to allow the community to tap and utilise water for their
domestic purposes. This will reinforce and enhance Marange Resources’ corporate-social
responsibility initiatives for the Marange community.
Two concrete tanks reinforced with steel the 1st with a water-holding capacity of 200,000l
and the 2nd with a water-holding capacity of 5,000,000l will also be constructed
References 1. Applied Thermodynamics. Estop and Mckonkey
2. Perry’s handbook for Chemical Engineers, Robert Perry &Don Green.1934
3. www.fluidflowinfo.com
4. www.sciencedirect.com/science/journal