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REPUBLIC OF BOTSWANA

ANNUAL REPORT

OFTHE

GEOLOGICAL SURVEY

DEPARTMENT

FOR THE YEAR

1986

PRICE: P3,OO

PRINTED BY THE GOVERNMENT PRINTER. GABORONE. BOTSWANA

1. GENERAL

The Geological Survey Department remained within the

Ministry of Mineral Resources and Water Affairs and continued

with its main functions of gathering assessing and disseminating

all data related to the rocks, mineral deposits and groundwater

resources of Botswana. The departmental organisation changed

slightly during 1986 so that it now consists of the

Directorate, four operational divisions of Field Geology,

Economic Geblogy, Hydrogeology and Geophysics together with

an administrative division. Support to the main divisions

continued to be provided by the Chemistry and Industrial

Minerals laboratories, Drawing Office, Library and Records and

Drilling Sections.

The staffing position within the technical and profes­

sional cadres remained very satisfactory because even the new

post of Principal--Geologist (Field Geology) was filled this

year. The post of coal geologist was also filled during the

year.

An expatriate officer Dr. J.M. Molepo, Senior Chemist

left the department at the end of the year when his three year

contract expired. Dr. Norman Lock continued as Assistant

Director, he went on end of tour leave at the end of the year.

Mr. Monty Chiepe, Assistant Geologist resigned from the civil

service to take up appointment with the private sector.

Satisfactory work programmes were carried out and

completed by all di vis ions dur i_ng the year. Within the field

mapping unit, most final reports of surveys conducted in the

1

previous years were completed and published. However the

following reports were either at compilation stage or their

fieldwork had been completed: Mmathethe QDS 2525A (Compilation),

Metlobo QDS 2524B (fieldwork completed), Jwaneng QDS 2424D

(bulletin in preparation), and finally Letlhakeng QDS 2425A

(compilation). During the year, the following new programmes

were initiated: revision mapping Mmamabula QDS 2326D/2327C

and Shashe QDS 2127A. The Okwa basement which forms a "window"

in the Khalahari was also mapped in detail during the year.

A new series of maps, the so called the "Khalahari series"

was started with the mapping of the Hanahai sheet at a scale

of 1:250 000.

The Economic Geology unit continued to monitor work by

the private sector by undertaking field visits to the various

Prospecting Licence areas and by ensuring that quarterly and

other reports are submitted to the department. Work by the

private sector continued to be directed to the search for

diamondiferous kimberlites, base metals, platinum group metals

and gold. Work on the review of industrial minerals was

continued on the Serowe-Palapye-Mahalapye and the Francistown-

Selibe-Phikwe clusters. Calcretes at Ngopilo in the Southern

District were evaluated for their quicklime production

suitability.

The hydrogeology division continued with its development

projects and ~ith the monitoring and supervision of work by

consultants. During the year, final results from groundwater

projects at Maun, Kanye and Molepolole/Mochudi were received.

2

i !

t ~'

I

A number of new groundwater projects were started this year.

These included the Serowe Groundwater Resources Evaluation

Project which is being undertaken by Swedish Geological

Company and the Kanye phase 11 project which is being carried

out by BRGM. The terms of reference for the Mmamabula > •

Project were prepared and a decision was made to undertake

the project in two phases.

An agreement on yet another project on the research on

groundwater recharge .was signed when the Netherlands

Government agreed to finance it. The hydrcgeological mapping

programme which started in 1978 was finally completed in

December.

Within the Geophysics Unit, the airborne magnetic survey

of eastern Botswana was completed during tr_e year apd this

now means that the whole country is covered with airborne

magnetics. The unit continued to provide advice on all the

groundwater evaluation projects which had a geophy."ics input.

Funding for two projects: the Geophysical exploration of

the Nosop-Ncojane Basins and the Petroleum Resource Investi-

gation of the three basins: I!cojane, I!osop and Passarge were

secured from the EEC and Petro Canada. These jJrojects are

due to start in mid 1987.

In the.support section the Drawing Office continued the

production of maps and diagrams accompanying geological

reports, bulletins and memoires. While the Chemistry and

Industrial mineral labor'atories provi.,d:ed the analytical

facilities to other se.ctions within the depar'tment. The

3

drilling unit provided all the dr'U.Llne; I.nput; required by the

department.

The two CIDA projects continued to run smoothly during

1986. The projects include the driller training project

which was successfully completed during the year and the

localisation of the GeophysiCs Unit project. In 1986 one

student went to Canada to undertake studies in geophysical

technology at Cambrian College.

The Vumba project, 2 bilateral project sponsored by the

German government ran smoothly during 1986.

~. Hydrogeology Division

5.1 Introduction

The staff situation remained unchanged during

1986, as far as the established posts are

concerned. The number of trainees however,

has increased, with one Assistant Hydrogeologist

joining the Division in July and two

trainees at the technical level, one starting

training in February and the other in April.

The planning and implementation of groundwater

projects and the supervision of consultants in

the execution of their contracts as well as the

co-ordination of prcjects has put a high demand

on the manpower of the Division. During the

course of 1986 the final results from the ground

water investigation projects Maun, Kanye and

Molepolole/Mochudi were received and their

results and conclusions incorporated into the

regional and local water resources scenario.

The Serowe Groundwater Resources Evaluation

Project which is scheduled for completion in

October 1987 generated some early data and step

by step increased the knowledge on the water

resources in Karoo formations west of the

Village. Investigations of the dclomite aquifer

basin south of Kanye continued under a second

phase in September. The contract was again

19

awarded to BRGM. After the decision, to implement

the groundwater investigations in the Mmamabula

area in two separate phases was taken in August,

terms of reference were prepared with the aim to

start the first phase of the project towards the

middle of 1987. Phase one of the project being a

compilation and evaluation of existing data will

be financed from local sources.

An important step regarding the implementation of a

groundwater recharge research project was achieved

when the Government of the Netherlands agreed to

finance the project. December saw the signing of

an agreement and operations plan by the Geological

Survey, the University of Botswana the Amsterdam Free

University; they will carry out the project as a

joint venture.

The hydrogeological mapping programme which started

in 1978 was finally completed in December with the

submission of the draft for map sheet 7. Financial

constraints precluded an extension of the groundwater

monitoring networks. Designs of additional

observation systems for crystalline basement and

Waterberg areas were almost completed by the end of

the year. With the financing secured for the

recharge research project there is now hope that

the Ministry of Finance and Development Planning

20

will allocate the funds requested for the monitorin~

project in 1987.

Working together with the Department of Water

Affairs, the Department of Town and Regional

Planning and the Water Apportionment Board, the

Geological Survey gave its contribution in the

field of water resources protection and pollution

control. Groundwater protection zones where

designed for wellfields at Ramotswa, Serowe,

Palapye and Kanye.

The research work and the projects carried out by

the Division or executed under its supervision have

greatly increased the knowledge of the nature of

groundwater occurrence in the country.

At the same time the professional capability in the

Division has been strengthened. Its involvement in

all important activities and in decision making in

the water sector has further reinforced the standint

of the department in the national water scene.

5.2 Development Projects

5.2.1 GS-10 Evaluation of Underground Water Resources

5.2.1.1 Water Supply for Maun and Hydrogeological Survey in

the Kanye and Molepolole/Mochudi area

Consultant: Bureau de Recherches Geologiques et

Minieres (BRGM), Orleans/France.

21

Maun area: The final ,report was much delayed and

submitted in May. Results: A wellfield was

established in a sandy infilling of a young graben

structure three kilometres west of Maun. The small

groundwater basin is recharged by the Shashe River

whose course follows the tectonic structure. From

the wellfield, up to 1 800 m~per day can be

abstracted provided river flow occurs annually.

This failing, only 900 m' per day can be pumped

during a second and third year of no recharge.

Thereafter the resource is exhausted until the

time when fresh flooding introduces replenishment.

The graben structure has a longitudinal extent of

approximately 12 kilometres. The wellfield

occupies only 4 kilometres. Additional resources

are likely to exist and could be developed with an

extension of the wellfield.

Kanye area: The final report was much delayed and

received in May. Results: The Dolomite formation

has a good groundwater potential.

The basin is however highly complex hydraulically.

Shear faults act as major groundwater drainage

features. Water quality is good. The time

allocated for the study proved insufficient in the

face of the complexity of the hydrogeology, so

that a reliable assessment of the resource was not

possible. Results in general were judged

encouraging and a follow-up project phase went

22

into planning. Under the French financial protocol

funds became again available and after negotiations

with BR GM in April the contract for phase 11 was

awarded to BRGM in June. Work for the project

commenced in September. By December an extensive

climatological and hydrologic monitoring network had

been installed and detailed geological field mapping

combined with airphoto and satellite imagery

interpretation carried out. The contract for drilling

and test pumping works was awarded to a local company

Geotest (pty) Ltd. in December.

Molepolole/Mochudi area: After long delays the final

report was received in June. Results: The predomi­

nantly arenaceous Waterberg formation is folded into

a wide WSW to ENE striking sync line which is in turn

broken up into a series of graben and horst structure$

Widespread dolerite intrusions have been identified.

The formation constitutes a fracture aquifer with

moderate but renewable groundwater resources.

Molepolole and Mochudi could be fully supplied from

these local resources meeting their demands up to

the mid nineteen nineties. Twelve target areas for

further exploration have been identified.

Fracture zones must be the target for drilling and

the most promising directions have been determined.

Groundwater quality is good near recharge areas but

saline water is found in discharge areas along the

23

. 5.2.1.2

axis of the syncline. Frequent very deep water

strikes and the occurrence of water bearing the

chemical characteristics related to carbonate

formation suggests the possible existence of a

second aquifer in Transvaal dolomite underlying the

Waterberg formation. A departmental programme was

initiated in July with the objective to study this

aspect in more detail (refer 5.3.2) .

Serowe Groundwater Evaluation Project

Consultant: Swedish Geological Company (SGC),

Sweden. Field work was more or less on schedule.

Seventy percent of all exploration boreholes have

been drilled and aJI water yielding boreholes were

pump tested. Geophysical borehole logging was in

pace with the drilling progress. The installation

of a monitoring network was completed in February

and since then routine observations have been

carried out. A computerised aquifer model has been

established which was updated regularly as new data

i.s generated. Drilling results and geophysical

data have led to a detailed geological model of the

project area which is complemented by a large

number of hydraulic formation parameters.

Long delays have been experienced with the submission

of technical reports. The airborne survey was

completed in January, the report however was only

submitted in December, five months behind schedule.

5.2.1.3

Still outstanding in December was the report on the

interpretation of airborne VLF and Slingram. An

even longer delay occurred with the production of

the report covering the interpretation of airphoto

and satellite imagery, it was delivered eleven

months behind schedule. The consultant clearly has

great problems in this area of the project manage­

ment. The fact that technical reports are produced

in Sweden may be one of the reasons for the delays.

Lephephe-Mmamabula-Limpopo Groundwater Investigatiop

Project,

In August a decision was made to execute the

prcject in two phases. Phase one: Compilation and

evaluation of all existing data with the aim of

establishing a regional picture of tregeology and

hydrogeology in the project area, based on which

target areas for detailed groundwater investigations

will be delineated.

Phase two: Groundwater exploration in the target

areas, groundwater resources assessment, demarca-

tion of future wellfield areas. Phase I consists

of two components. The interpretation of aeromag­

netic data, and the evaluation of existing

geological and hydrogeological data. Terms of

reference for the geophysical component were

prepared in December. The consultancy will be

financed from EEC funds. The same company executing

the aeromagnetic data interpretation for eastern

25

5.3

5.3.1

5.3.2

Botswana has been invited to tender for the Mmamabula

contract.

Terms of reference for the data evaluation contract

were in the drafting stage at the end of December.

Financing of this contract will be from local funds.

,Departmental groundwater exploration projects

Letlhakeng groundwater investigation project Phase 11

Report compilation had reached an advanced stage by

the end of December. Sandy facies of Karoo has been

identified in a wider area near Botlhapatlou. Water

quality is good. Resources are of considerable

magnitude warranting detailed exploratory work.

The area will be proposed for further project work.

Groundwater potential assessment for the Waterberg

between Mochudi and Molepolole

Indications for the possible occurrence of fractured

and karstic Transvaal dolomites under the Waterberg

formation revived the project and set new targets.

Groundwater circulation within the Waterberg rocks

is restricted to discrete fracture zones, conditions

which make groundwater exploration difficult and

costly. Fracture porosity could however be well

developed in the dolomites, in particular along the

contact with the overlying Waterberg and along

fracture zones; there could even be karst developed. If'this' is the case then water could be tapped

26

f

5.3.3

from the dolomite at better success rates and higher

borehole yields. A core drilling programme was

planned with the aim of probing for the possible

occurrence of dolomite, to delineate its areal

extent and to investigate its hydraulic nature. In

addition the coring serves to gather more informatio*

on the Waterberg lithology. The drilling of a total

of 1900 metres is planned.

Drilling commenced in March. The first site near

Sasakwe found fractured and karstified dolomite.

At the second site near Matematema no dolomite was

encountered. Here Waterberg is in direct contact

with Kanye Volcanics.

Drilling progress has been extremely slow due to

frequent break downs of the aged drilling rig.

Groundwater potential assessment for the Waterberg

formation east of Mochudi

A borehole survey covering Waterberg east of Mochudi

as far as the Limpopo was carried out. Borehole

locations were determined and plotted on maps. Where

possible water levels were measured and water

samples collected as well as borehole yields

estimated. Little progress has been made with the

data evaluation due to the long leave of the officer

in charge and commitments with consultants supervision.

5.4 Hydrogeological Mapping Programme

With the finalisation of the drafts for map sheets

27

HYOROGEOLOGICAL RECONNAISSANCE MAP OF THE REPUBLIC OF BOTSWANA AT SCALE 1 : 500 000 PROGRESS IN MAPPING AS AT 1.1.1987

Pubished

L:J At press

F'"l Awaiting production Ld in Orn";ng OHice

::::: :.:: 7:::: ..... .... . .. . ..... ... . .. .

28

______ +-____ ~~~o

I[D1TII Under production Ll..l.LUl1 in Drawing OffICe

Under preparation

[~] Uooer revision

i

9, 10 and 7 the secies of eleven m3.ps of the

J-lydrogeological Reconnaissance Map in scale

1 :500 000 ha,s been completed. Seven authors have

contributed to this programme which was started in

1978.

Map sheet 8 was published in April. And cartogra­

phic processing of sheet 9 and 10 started in October.

5.5 GroutLdwa ter moni tor i ng

Monitoring of selected aquifer basins continued

throughoe·t the year. B"tween March and September

observations included the Kanye dolomite aquifer.

This was done to have continuity of records betweEn

the first and second phase of groundwater projects.

Plans for the installation of new networks in south

eastern Botswana were prepared but could not 0e

implemented because fWJds for the project have not

come forward.

5.6 Borehole Records Archive and Computerised Data Bank

The updating of records continued as a routine t~sk.

Simultaneously additional areas were incorporated

in the new series of borehole locations maps. Data

for 2313 boreholes were cvded and crltered into the

data base. The index map enclosed shows the

progress achieved with the upgraaing ef borehole

location maps an,i the computerisation of data.

29

GEOLOGICAL SURVEY DEPARTMENT >c

PROGRESS IN COMPUTERISATION OF HYDROGEOLOGY WELL RECORDS AS AT 1.1.1987

.I-----Pi

c -

Cl REP\J8UC Of BOTSWANA

• "AV

.J

SOUTH

30

g{d Updated maps

Iii111 Updated maps, .!! .:; partially computerised

R."l?I Updated maps, ~ computerised

o Partially computerised

r

During 1986 a total of 166 Government boreholes were

registered and 131 private boreholes.

5.7 Consulting Services for Government and the Public,

Membership on Committees

The provision of professional advice to the public

and the release of borehole data is an all year

round task.

Government bodies which have received consulting

services are listed below:-

- Southern District Council: Demarcation of

groundwater protection areas for the Kanye

wellfield.

- Department of Water Affairs: Member of the

Working Group Ramotswa wellfield and

Gaborone Dam Catchment area protection

measures. Demarca ti:on 0)' groundwa ter

protection zones for the ~amotswa wellfield.

Comments were prepared for a number of

consultant reports related to hydrogeolo­

gical issues.

Continued technical advice was given to the

Water Apportionment Board. Reports on the

monitoring of the Jwaneng and Orapa well

fields prepared by Debswana were checked

and comments submitted to the Board.

The Board commissioned the department with the

31

forming of a working group with representatives from

BPC, DWA and DGS. The brief given to the working

group: establish an appropriate monitoring system

for the Paje wellfield to determine and agree on

appropriate measures for the monitoring of the

environment of the ash ponds near the Morupule Power

Station. A full agreement had not been reached by

the end of the year.

The working group dealing with the pollution of the

Lobatse aquifers continued its activities. LTC and

BMC entered into a trade effluent agreement which

opened up the way for design and construction of

evaporation ponds to receive the tannery effluents.

BMC submitted designs for the scheme which were

approved by the working group and construction work

started in December.

5.8, Hydrogeological research programmes

5.8.1 Co-operation with national and international

institutions in hydrogeological research

Established co-operation links were maintained and

strengthened further with the following institutions.

University of Botswana and Free University of

Amsterdam: The Government of the Nertherlands has

agreed to fund a three year study programme proposed

by the Geological Survey Uepartrnent and the Univer­

sity of Botswana, the project title is "Groundwater

Resources Monitoring and Recharge Studies". The

32

project has two components:-

a) groundwater resources monitoring and

b) recharge studies.

(b) is financed by the Dutch Government, whilst

part (a) is to be financed from development funds

under NDP VI. The recharge study will be under­

taken as a joint venture between the University of

Botswana, the Free University of Amsterdam and the

Department of Geological Survey. A plan of

operations has been drawn up and agreed upon by all

parties in December. The start of the study

project is scheduled for June 1987.

With the departure of Dr. J.J. de Vries, the

lecturer of hydrogeology at the Geology Department

of UB, there has been no further research activity

at UB in hydrogeology. UB has however confi.rmed

that the co-operaticn with GS would continue with

the arrival of his successor.

Federal Institute for Geosciences and Natural

Resources (BGR), Hannover: Landsat imagery specially

processed to enhance the vegetation signal was

supplied by BGR. It covers the whole area of

Waterberg formation occurrence between Molepolole

and the Limpopo River. The imagery interpretation

will be carried out by the department early in 1987.

It has been agreed that BGR will ass.ist with the

production of the planned Groundwater Resources

33

5.8.2

5.9

5.9.1

Map of Botswana in scale 1:1 Mio by seconding a

hydrogeologist and a cartographer during the first

half of 1987.

Departmental research programmes

Study of hydrochemical facies of groundwater in

active recharge areas (southeast Botswana) and in

areas under Kalahari beds cover with insignificant

recharge are investigated. Hydrochemical provinces

shall be delineated and hydrochemical evolution

processes be studied. Where possible regional flow systems shall be traced.

The study looking at southeastern Botswana came

close to finalisation whilst the second study

covering mainly the Kgalagadi District started in

June. A water sampling programme was carried out

to complement the data stored in the CS archive and

to obtain samples for groundwater age determination

Staff

Staff assignment

Principal Hydrogeologist - Heading the Division

Dr. M. von Hoyer

34

- Coordination of divisio~

nal work programmes.

Planning of work progra­

mmes together with Senior

Hydrogeologist and general

work supervision.

Supervision of the ground

water project Kanye

Phase 11 as from

September.

Identification of new

projects, preparation of

project proposals, terms

of reference and contract

documents. Co-ordination

of the hydro geological

mapping programme. Repre

sentation of the depart­

ment in various committe~

and working groups.

Training of counterparts.

Senior Hydrogeologist - Supervision of the Serowe

Dr. S. Keller groundwater project.

35

Planning and execution of

the groundwater investi­

gation project aimed at

the resources assessment

in the Waterberg Forma­

tion between Molepolole

and the Limpopo River.

Together with the Princi­

pal Hydrogeologist

planning of work and

Hydrogeologist I

H. Timje

Hydrogeologist 11

R. Hargreaves

36

research programmes.

Supervision of training

activities for junior hydro

geologists and guidance with

individual research studies.

Training of counterparts.

- Letlhakeng groundwater inve

stigation project, Phase 11,

a desk study. Data compila

tion, data analysis and

interpretation, compilation

of a comprehensive report.

Part time supervision of

core transfer to the new

core store. Assistance to

DWA with the evaluation of

tenders for borehole siting

contracts.

- In charge of the borehole

records archive and the

computer data bank as well

as the groundwater monito-

ring programme of the depart

ment. Professional advice

to Government and the public

regarding general hydrogeo-

logical information and

I !

Hydrogeologist III

E. Selaolo

borehole data. Planning and

organisation of day to day

archival work and work

programme for records

upgrading. Supervision and

control of the work of

Technical Assistants working

in the archive, the compute-

rised data base and the

monitoring programme. Active

participation in the work of

the departmental Computer

Committee.

- Refinement of storage calcu-

37

lations for the Ramotswa

wellfield. Compilation of

the hydrogeological map no.

7 in scale 1 :500 000 and a

map of scale 1:1.5 Mio

showing depth of groundwater

for the entire country.

Organisation and conducting

of a training course for

Technj.cal Assistants enti t-

led "Basics of the hydrogeo­

logy of Botswana" (3 weeks)

including the design of

~---------------------------------------------------------------------------------------'r

examination papers and test

result marking. Preparation

of a paper on groundwater

recharge to be presented at

an international workshop

in 1987.

In November attendance of

the international. training

session "Water pollution

control" held at Sophia­

Antipolis/France.

Assistant Hydrogeologist - Compilation of the hydrogeo-

P. Phofuetsile logical maps No. 9 and 10,

Assistant Hydrogeologist

G. Gabaake

38

completed. Commenced with

the MSc-project studying the

hydrochemical characteristics of groundwater in the Kgala­

gadi District and regional

groundwater flow systems.

A borehole reconnaissance

and water sampling was

carried out. Samples were

also taken for groundwater

age determination.

Joined the Division in July.

Compilation of an updated

edi tion of the Bibliography of

the Hydrogeology of Botswana.

Together with S. Keller

hydrogeological inve0tigatio~

of the Waterberg formation

between Molepolole and

Mochudi and aSsessment of its

groundwater potential. Field

supervision of the drilling

programme undertaken to probe

for the possible occurrence of

Transvaal dolomite beneath

waterberg cover.

Senior Technical Assistant- Completion of the borehole

J. Keakile

39

survey in the Waterberg

formation east of Mochudi.

Completion of a water bore­

hole survey in selected areas

near Gaborone, lVIelepolole and

Mochudi. This was in preparation of

new groundwater monitoring

networks. Borehole survey

in we~i tern Kweneng and

Kgatleng in connection with

the compilation of map sheet

7. Groundwnter sampling in

the Kgalagadi District.

Design for the modification

of a test pumping nnit to fit

the special requirements of

flow meter logging in bore

holes; also works supervision

Testing of the new plant in

the field together with the

Geophysics Division.

Senior Technical Assistant - In charge of the up-dating

K. Ntesang of the archival borehole

records, attending to in­

coming borehole data sheets,

processing of data, service

Senior Technical Assistant

K. Leetile and Technical

Assistant J. Phiri

Technical Assistant

A. Mogotsi

Industrial Class

M. Montsho & B. Mohamadi

5.9.2 Staff Training

Hyrlrogeologists

to the public.

- Groundwater monitoring.

- Up-grading of bore hole loca-

tion maps, data entry on the

computer data base, data

retrieval, digitising bf bore

hole location coordinates. Cartographic drawing for

various departmental reports.

- In charge of the dri.ll sample

store; working under the

supervision of R. Hargreaves.

40

E. Selaolo received training in the Serowe Ground

water Project ill practical field \'iC'rk awl hydro-

geological work methods, e.g. pump testing, packer

testing, drilling supervision, geophysical bore­

hole logging, aquifer mcdelling. In November he

attended a two weeks training session on "Water

pollution control" held at Sophia-Antipolis/Franc ..

C. Marobela'continued with his M.Sc. - studies at the

University' College London. In August he success­

fully completed the first study year.

P. Phofuetsile continued his research work under

the guidance of S. Keller. The work leads towards

his M.Sc.- project. He received training in the

Serowe Groundwater Project with an emphasis on

practical field work and hydrogeological work

methods, e.g. pump testing, drilling supervision,

geophysical borehole logging.

G. Gabaake works under the guidance of S. Keller

in the Waterberg groundwater project. This is

planned to lead into his M.Sc.-project.

T. Kgole completed his first study year at

Cambrian College, Sudbury/Canada, where he follows

a course in Geological Engineering Technology.

A. Mogotsi received training in the use of the

computer data base GS-H1.

J. Seilhomo & N. Ramotsoko joined the Division as

41

new trainees, Setlhomo in February and Hamotsoko

in April. They both completed their training in

cartographic drawing in the Drawing Office of the

department. N. Ramotsoko received field training

in the Serowe groundwater Project from October to

November mainly in the technical and logistical

aspects of drilling and test pumping. His

training then continued in the Kanye project as

from December. Here groundwater monitoring is

added to the programme.

J. Setlhomo familiarised himself with the organi­

sation and logistics of test pumping operations

under J. Keakile as his training officer.

P. Kekopakgomo failed to achieve satisfactory

results in the cartographic drawing course.

During the first weeks of his field training it

became apparent that his mental instability made

him incapable to further pursue training in the

field work. His training programme was termina­

ted in November because of his particular problem.

From 3.3 to 24.3 a training course was held at

the department on "Basics of the geology and

hydrogeology (iJf Botswana". It was attended by

Five Technical Assistants from the Department and

five driller trainees from the Department of

Water AJfairs. From Geological Survey three

trainees passed the course test.

42

5.10 Publications

J.J. DE VRIES, M. VON HOYER: Groundwater recharge

studies semi-arid

Botswana - a review.

Proceedings NATO­

sponsored workshop

Anatalya/Turkey, 1987.

A. GIESKE, E.T. SELAOLO A proposed study of

recharge processes in

fracture aquifers of

semi-arid Botswana;

Proceedings NATO­

sponsored workshop

Antalya/Turkey, 1987.

6.3.4 §erowe Groundwater Evaluation Project

Because of thick surficial cover, this groundwater

evaluation project has an extensive Geophysical component.

During 1986 a 7500 kilometres line airborne survey was

completed. The survey was flown at an average ground

clearance of 20 meters with a 400 meter.s line spacing,

and included magnetic, VLF a l1d 2 frequency coaxial AEM.

Ground follow-up with magnetic, EM and VES has been done

at 27 sites and Geophysical Borehole logging has been

completed in a dozen boreholes.

The results from the Geophysical surveys will be used in

the design of a numerical groundwater model to assess

the resource potential of the area. The project is

scheduled to be completed in 1987.

6.3.5 Kanye Dolomite Groundwater Basin

Hydrogeological Investigation, Resources Assessments and Development Pro,ject. Phase 11

This project is a follow-up to a project terminated in

early 1986. It is concentrated in 5 areas south~west of

Kanye. The Geophysical component during 1986 was related

to detailed structural investigations and borehole siting.

The techniques employed were magnetic, electric sounding

and profiling and electro-magnetic. This project will

continue throughout 1987. Geophysical borehole logging

will be done on all opened borehole drilled during the

project.

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6.3.6 Groundwater Resources Investigation, Lephepe-Mmamabula­Limpopo Area

This project was (structured and prepared for) planned,

designed and submitted to the tendering process. Terms

of reference for a detailed aeromagnetic interpretation

were written. Phase I of the project is scheduled to

take place during 1987.

6.3.7 Groundwater Geophysical Methodology Project

This project has been formulated and a project memorandum

written. The key elements of this projec-t include:

compilation of previous groundwater geophysics work in

the country, identification of problem areas, development

of appropriate solutions, publication of an application­

oriented handbook on Groundwater Geophysical Methodology.

6.4 Internal Project

6.4.1 Transvaal Dolomite Project

This internal project was initiated at the request of the

Hydrogeology Division. Its purpose is:

(i) To detect the presence of dolerite in proposed

drilling area.

(ii) To check if the geophysical techniques easily

available could supply stratigraphic information

down to the Transvaal Formations Levels.

Grids have been cut on sites with known stratigraphy to

analyse the formations' response and over proposed drill

sites to determine stratigraphy. Five ~i~es are being

investigated with induced Polarisation and Resistivity

Methods.

47

be smaller and weaker.

6.4.4 Dinokwe Magnetic Anomaly

A ground magnetic survey was carried out over what is

thought to be the strongest airborne magnetic anomaly

in Botswana about 12 kilometers northeast of Dinokwe.

The survey revealed a 40 000 nT anomaly of an arcuate

shape and i' bout 600 meters long. Follow up drilling

indicated that the anomaly is caused by banded ironstones

in upper Waterberg sediments.

6.4.5 Geophysical logging of water boreholes in dolomite and Waterberg formation in South East Botswana

This internal project was initiated at the request of

the Hydrogeology Division. Boreholes selected by the

Hydrogeology Division are logged with a standard suite

of tools. Some of the logs are performed while the hole

is being pumped to locate points of water entry and

quantify water inflows.

6.4.6 Groundwater Geophysics Seminar

Geological Survey Departmen~s contribution to the seminar

(under the auspicies of BGA) was in two parts; Letlhakeng

groundwater project and review of direct Groundwater

Geophysical Techniques.

6.4.7 Morupule Power Station Pollution Monitoring

This work has been contracted out to a local contractor.

Geological Survey Department involvement has been to

comment on the work and a site visit.

49

In order to determine trace quantity of arsenic (parts

per billion level) in soil samples by the hydride generation

method, Parking-Elrner' IVJHS-20 Mercury/Hydride generation

system was procured. Necessary research was carried

out for the evaluation of appropriate reliable analytical

method for the determination of trace quan~ity of

arsenic and mercury. A number of soil samples were also

analysed for mercury.

9.3.2 Serowe Groundwater Project (Swedish Geological Company)

Serowe groundwater resources evaluation project was

contracted out to Swedish Geological Compar.y in the

second ha1f of 1985. Under the agreement, the Chemistry

Laboratory carried out all the water analysis required

for the project. 166 borehole water samples submitted by

the Swedish Ge010gical Compar.y were analysed and reported

during 1986. Many more samples are expected during the

first half of 1987.

9.3.3 Kanye and Molepolole!Mochudi Groundwater Project

(Undertaken by Bureau de Recherches Geologiques et

Minieres) ;

The above groundwater project was contracted out to

BRGM. Under the agreement, the chemistry laboratory

provided the necessary anelysis required by the project.

A number of soil, rain water, and borehole water samples

were analysed for the evaluation and interpretati~n of

geological, hydrogeological, hydroche~ical and

climatological data.

67

9.3.4 Geochemical/Rock/Mineral Analysis Records, Archive and

Computer Data Bank

Since 1985, GS-17 (West Germany) Vumba green Schis't

belt project generated about 20 000 geochemical

samples. These samples were analysed for nine

elements giving rise to 180 000 chemical data. The

data were systematically stored in Apple lIe computer

using MAX software provided by Federal Institute for

Geosciences and Natural Resources (BGR). A large

number of data generated from rock and mineral analysis

were also stored in 3.3 diskette using MAX software.

The search, listing, statistical calculation, plotting

etc. were carried by BGR geologists using the raw

data for evaluation of geochemical anomalies.

9.3.5 Setting up a Maun Water Analaysis Laboratory for

Department of Water Affairs:

The setting up of a water analysis laboratory in Maun

for water resources development and monitoring project

of Okavango delta was proposed by the Department of

Water Affairs for quite sometime. In order to implement

the proposal, training of the technical staff of

Water Affairs started in 1983 in the Chemistry Lab.

Lobatse. A total of four technicians were trained in

laboratory methods of water analysis. Necessary advice

was also given regarding the procurement of relevant

eqUipment, chemicals etc. Following the discussion

with the Department of Water Affairs in the month of

May regarding setting up of an independent laboratory

68

in Maun for monitoring water samples from various

stations of Okavango Delta, the Principal Chemist spent

the 10th and 11th June in Maun and organised the

laboratory for the Department of Water Affairs.

9.3.6 Pollution of Peleng River and surrounding Aquifers

The provision of professional and technical advice to

members of the public as well as other Government and

paras tal organisations is an all year round task and

largely consists of providing analysis of water samples

and advising suitability for human consumption, chemical

pollution etc.

The Water Apportionment Board commissioned the

Geological Survey Department under the chairmanship of

Deputy Director with representatives from BMC,

Department of Water Affairs, Lobatse Town Council and

Local Government and Lands to establish a technical

solution of the pollution problem.

The chemistry laboratory was represented in all the

meetings and val'-lable contributions were made to

establish the technical solution of the pollution problem,

to draw up the trade effluent agreement between B.M.C.,

and Lobatse Town Council and to finalise the design of

evaporation ponds for tannery effluent.

9.3.7 Geological Survey Computerisation Report

An in-house study was undertaken within the Qepartment

in order to assess the existing computer set up and

future needs of the Geological Survey. The exercise

lasted 7 weeks from 15th April to 2nd June. The in-house

study was undertaken in order to provide the necessary

69