1. 1
Replenishment Dynamics of the Verugal
Heavy Mineral Sand Deposit
T.D.Igalawithana, P.W.G.Udayakumara, D.M.C.J.B.Dissanayake,
A.V.P.I.Karunarathne, S.W.M.Maduranga, K. Amalan and
* N.P.Rathnayake
*
Corresponding author –nalinratnayake@gmail.com
Abstract: Heavy mineral are prominently used in a wide range of industrial applications
with rapid development of technology. Eastern coast of Sri Lanka rich in heavy mineral
deposits as longer period of time with higher concentrations comparatively other heavy
mineral deposits in the world. The objectives of the study were to study about heavy
mineral replenishment in Verugal beach area and the replenishment rate of the deposit.
Heavy mineral sand deposits are dynamic mineral resources which are varying with time,
weather and several factors. With a proper idea of replenishment dynamics,
comprehensive mine plan for the extraction of heavy mineral sand can be commenced.
Studies about the heavy mineral sand deposit carried in South-west and North-East
monsoon periods. Collected samples were analyzed with sieve analysis, panning, grain
counting methods and magnetic separation, Bromoform analysis used as reproducing the
results. Through the results obtained, qualitative and quantitative analysis was carried
about the heavy mineral sand deposit. Variations in deposit dimensions with seasonal
weather changes, specific mineral concentrations and replenishment rates were analyzed
under statistical methods. Finally being considering rate of replenishment of the deposit,
a proper mining plan can be proposed to commence sustainably extract heavy mineral
sand. The block mining can be proposed as the best suitable method for the extraction
mineral sand deposit.
Key Words: Heavy mineral sand, Ilmenite, Replenishment, Sieve analysis, grain
count
1. Introduction
Heavy minerals have wide range of
industrial applications with the
development of technology. Heavy
minerals use for numerous applications
such as Titanium from Ilmenite and
Rutile uses for construction of planes,
medical equipment and Zircon uses for
ceramic industry and for construction
purposes. Heavy mineral is defined as a
mineral which is having the density over
3.2 g/cm-3. The heavy minerals are
basically derived from the weathering of
Igneous and Metamorphic rocks.
Eastern coast of Sri Lanka can be
mentioned as an area which consists
with few of the richest mineral sand
deposits in the world.
Dr NP Ratnayake
BSc(Hons)(Peradeniya),MSc(Shimane),PhD
(Hokkaido)Senior Lecturer , Department of
Earth Resources Engineering
T.D.Igalawithana, P.W.G.Udayakumara
D.M.C.J.B.Dissanayake,
A.V.P.I.Karunarathne, S.W.M.Maduranga,
Final year Undergraduate students in the
Department of Earth Resources Engineering,
University of Moratuwa. K.Amalan senior
research student, Department of Earth
Resources Engineering, University of
Moratuwa.

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Most of these areas consist with heavy
mineral deposits. In Sri Lankan heavy
mineral sand deposits consist
concentrations with 70% of heavy
minerals. These mineral deposits are
rich in concentrations with
comparatively other heavy mineral sand
deposits in the world.
Area nearby Verugal consists with a
large mineral sand deposit which is
currently producing a large amount of
valuable minerals annually. The area
which is called as the Verugal aru is
located at eastern coast around 50
kilometres southward from
Trincomalee. Verugal aru beach also
consists of with a mineral sand deposit
which spreads along an area more than
three kilometres.
Heavy mineral sand deposits are
dynamic deposits, which are changing
vertically and horizontally with the
time. Climatic conditions, Coastal
hydrodynamics such as following
factors affect those variations in
deposits.
 The current conditions as well as
the variations along the area
 The water-level conditions such as
tides and wave set-up
 The bathymetry in the area
 The sediment characteristics over
the area such as the size of
sediments
 The sources and sinks of sediment,
such as rivers and eroding coasts
 The wind conditions at the site and
the possible variations over the
site plus the adjoining areas
Studies about the pattern of
replenishment process will help to
design a mining plan to extract the
heavy mineral sand in most effective
way. This is really important to extract
mineral sand from the deposit in a
sustainable manner.
2. Methodology
2.1 Beach topographic survey
Beach survey was conducted within 4
km stretch from Kathiraweli south to
south most river mouth of Mahaweli
River. It was consisted with seasonal
monitoring of the site investigation,
beach morphology and transverse
profile survey in between before and
after North-East monsoon. Each
transect was located with distance of
500 m to each.
GPS coordinates of a planned survey
locations were plotted on a map and
using GPS receiver in the field those
positions were identified. For further
beach profile surveys on these locations,
fixed points were identified and plotted
for each survey line. Distances to the
mean sea level from above mentioned
fixed points were measured using
plastic measuring tape during two (02)
observation filed visits. Using the
levelling instrument and levelling staff,
level readings of the cross section of the
beach were taken along the planned
survey lines
2.2 Sampling and surveying
During the beach profile survey
sampling locations were selected along
the survey lines. Sample collection was
planned to collect representative
samples for the whole mineral sand
deposit. Samples were collected in
mean sea level, 5, 10, 20 and 30 m.
At each location, 3 samples were
collected at depths of 0.3 m, 0.7 m, 1 m

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respectively. Sample size was roughly 2
kg.
2.3 Laboratory analysis
Collected samples were analyzed under
following tests and procedures.
- Sieve analysis
- Panning
- Grain counting
- Bromoform analysis
- Magnetic separation
- Thin section analysis
Sieve analysis for mean grain size of the
samples was carried out in 108 samples,
collected in before and after North-East
monsoon. Panning was conducted to
separate and obtain heavy mineral
fractions of samples. Grain counting
under a microscope conducted to
account volumetric percentages of each
heavy mineral types in the samples.
Results were reproduced using
Bromoform analysis and magnetic
separation. Bromoform analysis of
selected panned samples was taken to
cross check the accuracy and reliability
of the panned samples. Thin section
analysis was carried out to verify the
identification of mineral types.
Magnetic separation was conducted to
reproduce the results of grain count.
3. Results and Discussion
3.1 Distribution of mean grain
sizes
Mean grain size variation of the Verugal
heavy mineral deposit was observed
before and after North-East monsoon
Figure 1 Mean grain size distribution
before North-East monsoon in Verugal
beach
Figure 2 Mean grain size after North-East
monsoon in Verugal beach
Mean grain size distribution along the
beach and transects has quiet difference
variation. Mean grain size of the sand
particles has decreased along the
southward direction during both
monsoon periods but it has good sorting
of grain sizes during North-East
monsoon rather than South-West
monsoon. Along the transects mean
grain sizes have increased and 300-400
µm grains found from mean sea level to
10 meter distance. Finer fraction of
heavy minerals found in 30 meter
distance this is mostly due to wind

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transportation of sediments and trapped
by vegetation.
3.2 Beach topography variation
Topographic variations in before and
after North-East monsoon have
observed. In this beach width, beach
height, beach profile variations
monitored.
Figure 3 Seasonal Beach width
variation in Verugal beach
Topography of the deposit area has a
significant change in monsoon period
with considerable variations. Beach
width has increased during the South-
West monsoon and eroded in North-
East monsoon. Beach widths have
increased southward direction from the
river mouth of Verugal in both periods.
3.3 Panning for heavy mineral
separation
Mineral samples were panned and
weights of the remaining heavy mineral
fraction have recorded. Distribution of
heavy mineral in the deposit was plotted
using contour maps comparing two
seasons.
Figure 4 Heavy mineral distribution
before North-East monsoon in Verugal
beach
Figure 5 Heavy mineral distribution
after North-East monsoon in Verugal
beach
Heavy mineral; distribution of the
deposit has decreased in the North-East
monsoon period rather than South-West
monsoon Because of increased river
discharge during North-East monsoon
heavy mineral concentration is high in
river mouth area. With the longshore
current heavy minerals have transported
towards south in the South-West
monsoon. Heavy mineral concentration
has decreased towards land slide, but
there is accountable increase in 30 meter
distance due to wind transported finer
heavy minerals trapped by vegetation.
0
20
40
60
80
100
120
VE 01 VE 02 VE 03 VE 04 VE 05 VE 06
Beachwidth(m)
Location
Before monsoon After monsoon

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4.4 Grain count analysis for
volumetric composition of
heavy minerals
Under a microscope, panned samples
were analyzed to have a volumetric
composition of heavy mineral fractions.
Figure 6 Mineral compositions of
Verugal heavy mineral deposit
In general Ilmanite is the dominant
mineral in the deposit and majorly
distributed near mean sea level. Garnet
and Zircon distribution have increased
towards land side due to settlement of
particles according to the specific
gravity of minerals. Ilmanite percentage
has reduced after North-East monsoon
and percentage of Garnet and Zircon has
increased. Other minerals do not show
any significant variation.
5. Conclusions
The Verugal mineral sand deposit is
dominated by river sediments which are
mostly composed of fine to medium
grained sand. Grain size of the sand has
decreased along the shore line from
river mouth area to southward. In
general beach sand shows finely skewed
near the MSL and symmetrical
distribution in other areas. Heavy
mineral distribution of the deposit is
higher near the mean sea level area due
to panning process in the South-West
monsoon. Deposit is dominant with
Ilmanite, Garnet and Zircon
respectively. Most suitable time to
commence mining of the deposit is
September to December during South-
West monsoon.
Acknowledgements
The authors would like to convey their
gratitude to Dr. A.M.K.B. Abeysinghe
Head of the department of Earth
Resources Engineering, Dr. H.M.R.
Premasiri, Senior Lecturer, Department
of Earth Resources Engineering and
final year project coordinator, Mr. K.
Amalan, Senior Research Scholar,
Department of Earth Resources
Engineering and all the technical staff of
the department who helped for the
success of this project.
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0
10
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Ilmanite Garnet Rutile Monazite Zircon
Percentage
Heavy mineral type
Before Monsoon After Monsoon

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