Jurnal Internasional
Jurnal Internasional
Jurnal Internasional
Geophysics Lecturer, Physics Department, Midlands State University, P/Bag 9055 Gweru, Zimbabwe
Undergraduate Student, Physics Department, Midlands State University, P/Bag 9055 Gweru, Zimbabwe
Abstract: Geophysics can make significant contribution to the life of mankind by skilfully helping in the precise location of valuable
concealed ore deposits of economic value. The aim of this study was to conduct a geophysical survey using ground magnetics on NMPL
north and south base metal blocks to detect disseminated sulphides which are associated with gold mineralisation located in Mphoengs,
Bulilimamangwe District of Zimbabwe. More specifically it sought to generate anomaly maps of the study area with the ultimate aim of
establishing beyond doubt regions with greater concentration of valuable gold deposits. A series of measurements were done and results
presented as anomaly maps. The project is located within a narrow corridor of variably altered talcose horn blend-chlorite schist and
serpentinites. This is a highly mineralized gold zone that has seen significant gold production in the past and shows potential for
discovery of major gold resources in the future. The study area is located within a geologic setting considered highly prospective for the
presence of a low tonnage high grade, bulk mineable gold deposit. The results really show the applicability of Physics to providing
practical solutions to real problems. The established anomaly maps are usable by the project client to plan and zoom in on the most
profitable regions of the surveyed area.
Keywords: Geophysics, magnetics, disseminated sulphides, gold mineralisation, potential, mineable deposit, anomaly maps
1. Introduction
Over the years, the need to precisely locate buried ore bodies
has intensified. The need for larger quantities of usable
mineral has boomed as technology and human population
soared to higher levels triggering the development of
advanced methods for exploration. Magnetics has emerged
as one of the methods used successfully to precisely locate
the position of valuable deposits of economic value making
it possible to contribute significantly to the advancement of
mankind. The aim of the magnetic survey was to investigate
subsurface geology on the basis of anomalies in the Earths
magnetic field resulting from the magnetic properties of the
underlying rocks. The concept of magnetics has long been
important and continues to be improving to date. Ground
magnetic survey is a type of magnetic survey that is
performed on the ground or on land. Ground magnetic
surveys are performed over small areas, with station spacing
of 10 -100m (Kearey et al. 2002). Magnetic method is a
common geophysical method used today in geology and
engineering geology in locating buried hills, geological
faults, intrusions of igneous rock, salt domes associated with
oil fields, concealed meteorites and buried magnetic objects
such as pipe-lines, etc (Parasnis 1979). All geological
structures, rocks, minerals, ore deposits and engineering
geological structures have magnetic properties that differ by
orders of magnitude rather than percentages (Milsom 2003).
Although most rock-forming minerals are effectively nonmagnetic, certain rock types contain sufficient magnetic
minerals to produce significant magnetic anomalies.
Similarly, man-made ferrous objects also generate magnetic
anomalies. Magnetic surveying thus has a broad range of
applications, from small scale engineering or archaeological
surveys to detect buried metallic objects, to large-scale
surveys carried out to investigate regional geological
structure. Magnetic surveys can be performed on land, at sea
and in the air (Lowrie, 2007). Consequently, the technique is
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2. Study Area
The Project Area is located 210 km south of the city of
Bulawayo in Bulilima Mangwe District. The claims within
the northern block of the project area are centred at
590,913.49
(UTMARC1950E)
and
7,653,021.07
(UTMARC1950N) and cover a combined total area of 205.7
Ha. All claims boundaries on the northern block have been
marked by fixed beacons.
Present access to the claims is via a provincial tarred
highway that heads south from Bulawayo to the town of
Plumtree. A district tarred road heads off from Plumtree
town towards Mphoengs Police Station for 63 km after
which there is a well maintained gravel road for 36 km up to
Mphoengs Police Station. The project area is located 3.8 km
directly southeast of Mphoengs Police Station. Access to the
Figure 2.1: Map of Zimbabwe showing the location of NMPL ground holding
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3. Methodology
th
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References
6. Conclusions
The magnetic signatures obtained from the surveyed area as
presented on the maps above and described in the
discussion, brings a very interesting and strong message
about the nature of the subsurface at Mpoengs which is there
for anyone interested to analyse and use. Based on these
reliable results, it can be argued that the area has economic
potential. Using the maps and the GPS one can zoom in and
precisely concentrate on the regions with magnetic high
signatures for economic exploitation of the resources
embedded in mother earth. Evidence from geology suggest
that those regions of high magnetic signatures are due to
sulphide bodies and are possible for mining interest for gold
minerals associated with disseminated sulphides. The main
disadvantage of magnetic methods in locating mineshaft is
when the in-fill material is similar in terms of magnetic
properties with the surrounding rock mass (McCann 1987).
This study showed that the magnetic method can be used
Author Profile
Bernard Siachingoma has done Masters in Geophysics. Presently
he is serving as Lecturer at Midlands State University, Zimbabwe.
His research interests include Geophysics. He is also a PhD
Scholar.
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