1. THE UTILISATION OF 2-D RESISTIVITY AND INDUCED POLARIZATION (IP)
METHOD TO DETERMINE THE IRON ORE BODIES FROM THE MAGNETIC
SURVEY RESULT AT KAMPUNG MELAKA, KUALA LIPIS, PAHANG
Adreina Shamelia SH1
, Fathin Nur Amirrah MN1
, Kasdi Nata S1
, Dr Mohd Rozi2
1
PERMATApintar® National Gifted Center, Universiti Kebangsaan Malaysia
2
School of Environment and Earth Science, Faculty of Science and Technology,
Universiti Kebangsaan Malaysia
ABSTRACT
In Malaysia, on mineral that has high potential to be explored is iron ore. To identify the iron ore
bodies, 2-D resistivity is used in this study whereas Induced Polarization (IP) method is used to
differentiate between iron ore deposits and ground water beneath the ground. A small current was
injected into the ground by the electrodes and the resulting voltage difference between the electrodes
was determined which will present the resistivity measurement. By using the 2- D resistivity method,
iron ore can be detected by its low resistivity. Meanwhile, high resistivity indicates the presence of
ground water, residual soil, fresh rocks and weathered rock. A total of three survey lines with a total
length of 600 m is divided into three different lots, each has a total length of 200m. The study was held
at Kampung Melaka, Kuala Lipis, Pahang, Malaysia. Magnetic survey result was used to gain the
result from the collected data. The result shows that the iron ore underlying the surface from the depth
of 5m down until 30m was mostly located at lot 1 and 2 based on their low resistivity. The first lot
consisted of iron ore from 20% until 25%. The second lot indicated the existence of iron ore for about
30% to 35% whereas third lot only point out the existence for about 15% to 20% over each 200m
survey line.
KEYWORDS: Iron ore; 2-D Resistivity; Induced Polarization (IP) method; Survey lines
INTRODUCTION
The most common element in the Earth’s crust are oxygen, silicone, aluminium and iron at the
fourth place. Iron is mostly found in combination with other elements such as oxygen, and also in the
form of iron oxide minerals such as magnetite (Fe3O4) or hematite (Fe2O3) and other compounds.
Resistivity survey is a method used to find the subsurface resistivity distribution based on the
measurements made on the surface of the ground. The real resistivity of the subsurface can be assumed

2. from the measurements ( Loke, 2001). The resistivity of material is defined as the resistance in ohms
between the opposite faces of a unit cube of the material (Kearey et al.,2002).
The presence of Induced Polarization (IP) method in the instrumentation for magnetic surveys
has been the most advance system. The inversion of IP data can be done with the RES2DINV, a
computer program. Generally, there are two mechanisms for IP which are membrane polarization and
the electrode polarization effects. The clay minerals consist in the rock or sediment is responsible to
cause membrane polarization effect whereas the conductive minerals in rocks cause the electrode
polarization ( Loke, 2001)
LITERATURE REVIEW
Iron ore can be categorized into low-grade and high grade ore depending on the percentage of
the presence of iron compound. High-grade ore contains more than 60% of iron and perhaps, comes
from deposits of massive hematite formed by in situ enrichment of iron, usually a banded iron
formation. Low-grade iron ore, on the other hand, commonly contains 25-30% of iron and it naturally
forms iron-rich rock. Most of iron ore deposits in the world contains low-grade iron because of the
presence of other minerals, mainly silica. Demand of iron ore is increasing yearly among industry
players and iron ore is an important commodity besides gas, oil and gold (Rosli Saad et al, 2012).
Electrical survey method is currently the preferred method and requires taking measurement
on the ground surface in order to find the subsurface resistivity distribution. Various geological
parameters such as minerals, underground water and porosity are related to ground resistivity. To
measure the resistivity, current is injected through two electrodes which are planted into the ground
and the resulting voltage difference at two potential electrodes are then taken. An apparent resistivity
value can be measured from the current (I) and voltage (V) values,
IkVpa /
where k is the geometric factor which depends on the order of four electrodes. Resistivity meters
normally show a resistance value, so apparent resistivity is measured by
kRpa 
To find out the original subsurface resistivity, an inversion of the calculated apparent resistivity values
using a software in the computer must be carried out which is RES2DINV (Loke, 1999).
"Induced polarization (IP) is an electrical geophysical method to measure the effect on current
flow of charge storage beneath ground" (Rosli Saad et al, 2012). IP can identify disseminated minerals.

3. Overvoltage, the basic concept, occurs because of the characteristic of ground which plays the part as
capacitor when DC current is turned off, voltage calculated does not immediately drop to zero from
two potential electrodes but takes finite time to rot with time. Then, DC current is turned on and
voltage calculated takes same finite time to achieve steady value (Milson, 2003).
The most important parameter to be obtained from the IP method is chargeability of minerals
and rocks. Chargeability is defined as the ratio of the area under the decay curve to the potential
difference calculated before turning the current off. Real chargeability is the ratio of the secondary
voltage, Vs, or the over- to the observed voltage, Vo (Seigel, 1959)
METHODOLOGY
The 2-D resistivity and IP are the two electrical imaging methods that is used to conduct this
study. The 2-D resistivity method is responsible to determine the ore bodies from the contrast of
resistivity value but the IP method is utilized to secernate the chargeability of the subsurface between
ground water and iron ore. Two survey lines of about 100m each are used for every 3 lines which
make a total of 600m. The electrode spacing for the pole- dipole array used is about 5m. The software
used to process the data was the RES2DINV.
Study Area
The study area is situated at Kampung Melaka, in Kuala Lipis, Pahang. This site covers the
land area of 400 acres (Figure 1) and is located about 10 km away from Kuala Lipis town. Some 200
magnetic data were collected at the study area. The magnetic survey points were marked as KML
which refers to Kg. Melaka in our survey reference. The GPS reading was saved with the label
KML01A as for the first point at the first line. Each line has 3 points to be taken its location. The tags
are being continued until the last point for the third line. All these 3 points are situated in 3 different
places with different remarks.
The Instrument
The main instrument used for this magnetic survey were ABEM SAS1000 resistivity meter
and ABEM LUND ES464 electrode selector system. This system was laid out in a straight line where
41 stainless steelelectrodes were connected with multi- core cable. Only three active electrodes were
selected to be taken their measurements. The spacing between each electrodes was 5 metres apart for a
length of about 200m and about 30m in depth, based on Wenner spacing electrode array.

4. Figure 1: Resistivity meter and electrode selector system used in magnetic survey
RESULT AND DISCUSSION
Line 1
Figure 2: Line 1
Figure 2 above shows Line 1from KML01A to KML01B, covering the distance of 100m,
between KML01A and KML01B. Similarly, the distance from KML01B to KML01C is also
equivalent to the distance between the first two points..
Figure 3: The resistivity section (right side) and IP section (left side) of KML01 survey line.
From Figure 3, it is observed that the higher the number of the chargeability of the section, the
higher the abundance of the iron ore body. Result for Figure 3 shows the abundance of the quality iron
ore body is little. This is shown by the various colours of the diagram. The orange to purple part
means the soil of the site; whereas the blue to green part shows the abundance of the iron ore body on
the site. The red part of the Figure 3 indicated high quality iron ore. Figure 3 above shows the
resistivity test on Line 1. Based on the results of the test that had been carried out on Line 1, there are

5. obviously more soil and rock than the iron ore bodies itself. The iron ore that are abundance in the this
figure show its number near 100m and there are only small part of the iron ore shows the part of the
dark blue part of iron. There are a lot more non-quality iron ore than the quality iron ore itself. Most of
the section is filled with residual stone. It covers almost 50% of the diagram.
For resistivity section for Line 1, Figure 3 shows the abundance of iron ore body, including the
one with the mixed iron, which had been bonded with other element; such as silica. The resistivity of
the iron ore is used to the section of the iron ore on the site. The most accurate result is the
chargeability section. For Line 1, as the colour goes up, there less abundance of the iron ore body.
Line 2
Figure 4: Line 2
Figure 2 shows Line 2 which consist of 3 points. The distance between these points is about
100m each. That means that it is 100m from KML02A to KML02B, and also the same for KML02B
to KML02C.
Figure 5: The resistivity section (left side) and IP section (right side) of KML02 survey line.
The result for the resistivity at Line 2 shows that the potential iron ore is situated under the
weathered rock and followed by fresh rock. This is based on the colour of the graph as the blue part
indicates the presence of potential iron ore. As it also means that there are plenty of iron ore if the
number of the chargeability of the section is superior. Based on the results of the test, it seems obvious
that the iron ore at Line 2 is more than other two lines as it covers almost 60 meters from each side

6. with the depth of 15 meters from the bottom. The fresh rocks fill the depth for about 10 meters at the
first 80 meters length and the next 80 meters with a gap of 40 meters. This is because the orange and
brown parts are both show the fresh rocks while the green and yellow parts indicate the weathered
rock.
The profile of the IP result shows that it is covered by a thick soil with chargeability value of 10.3
– 93.3 msec. The pure iron ore which has chargeability value of msec02.0 is found to be at the
depth of from the surface until 20m downwards.
Line 3
Figure 6 : Line 3
This is a picture of Line 3 which consist of 3 points that have been taken from Google Earth
based on their coordinates. The coordinates were taken while the research was conducted. The
distance between these points are about 100m each which means that it is 100m from KML03A to
KML03B and also the same for KML03B to KML03C.
The survey line three is located at the highest place among the three survey lines. There was a
construction during the period of our research. The length of survey line is 200 m with 5.0 m spacing
for each electrode. The interpretation from the resistivity survey shows that the subsurface profile for
the line survey three consists of boulders as the main component m)762309(  . The dark blue
shows that there are small amount of quality iron ore in this profile m)1258.50(  . The potential
iron ore is found at the start and the end of the line survey about 40 m long. The centre of the profile is
fulled with weathered rocks and small parts of fresh rocks. Their thickness is about 10 m depth.
The IP result shows that the profile is covered by a thick soil with chargeability value of
msec2.712.12  . Pure iron ore with chargeability value of msec02.0 is expected to lies at 13.4-

7. 21.5 m depth.
Figure 7 : The resistivity section (left side) and IP section (right side) of KML03 survey line.
CONCLUSION
The iron ore at all three lines are shown to be about 15 - 35%. There is not much potential iron ore at
these lines. Line 1 came out to have average potential iron ore of about 20-25% while at Line 2, it has
the highest amount of potential iron ore which about 30 – 35%. As for Line 3, the estimated iron ore is
about 15-20%.

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