Geological Survey Department
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REPUBLIC OF BOTSWANA ;". ANNUAL REPORT OFTHE GEOLOGICAL SURVEY DEPARTMENT FOR THE YEAR 199J-; PRICE: P3,OO Printed by the Government Printer, Gaborone Botswana GEOLOGICAL SURVEY DEPARTMENT (Director: T. P. Machacha) ANNUAL REPORT OF THE GEOLOGICAL SURVEY DEPARTMENT FOR THE YEAR 1992 PUblished by The Director Geological Survey Department Private Bag 14, Lobatse, Botswana. With the authority of The Ministry of Mineral Resources and Water Affairs Republic of Botswana 1. GENERAL The Geological Survey 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 grouhdwater resources of Botswana. The departmental organisational structure continued to consist of the Directorate, four operational divisions of Regional Geology, Economic Geology, Hydrogeology and Geophysics together with an Administrative Division. Support to the main divisions was provided by the Drawing Office, Technical Records and Library, Chemistry and Mineral Dressing Laboratories. During the year the staffing position within the Department was consolidated with a full establishment of professional staff. There were no changes in the Directorate although the Deputy Director spent much of the year in Canada completing his PhD studies. The Principal Regional Geologist, Mr D P Piper, returned to the U K in July and was replaced by Dr R M Key who arrived from the U K in October. Within the Economic Division the evaluation of industrial minerals continued to be given priority with extensive investigations in the Dukwe-Matsitama, Selibe-Phikwe and Palapye areas. The writing of the gold monograph continued, as did the exploration for base and precious metals in the Maitengwe Schist Belt. Mineral exploration by the Private Sector continued at a high level throughout the year despite the global recession. At the beginning of the year there were 295 prospecting licences in force which increased to 297 licences by the year's end. 222 of the licences were for precious stones (diamonds), 56 for base and precious metals and 19 for other minerals. Within the Hydrogeology Division much of the activity was involved with the implimentation or monitoring of six major groundwater projects throughout Botswana. Five of the projects involve consulting companies and one (the TGLP Ghanzi/Makunda Groundwater Project) is being undertaken· completely by Department staff. Additionally there were a number of on-going groundwater research programmes which will eventually lead to a better understanding of the groundwater resources of Botswana as well as improving the techniques used to find this precious resource. The Division continues to monitor the groundwater resources which are presently being utilized; there is a National Monitoring Network established in the Department which is being fully computerised. Professional advice on groundwater was given to other public bodies throughout Government. The Geophysics Division continued to assist the Hydrogeology Division and Department of Water Affairs in groundwater resource evaluation and development projects. A groundwater methodology handbook was produced which will s'erve as a reference text for geophysical exploration for groundwater. The National Gravity Survey Database is being continuously upgraded, and there were over 19 000 records on the database by the end of the year. This represents a coverage of one station per 33 km 2. A seismological station became fully operational within Botswana during the year. This station is part of a global telemetry seismograph network which wil/ monitor seismicity in Botswana and neighbouring countries. An important role of the Regional Mapping Division continued to be 'the production of geological maps of quarter degree sheets of the better exposed parts of the country. Work continued on a number of these maps, with some geologists using their field information as the basis for post-graduate studies in the U K. At the end of the year it was also decide to produce geological maps of the poorly exposed parts of Botswana where there is a lot of mineral exploration. These maps wil/ be at a scale of 1 :250 000 in contrast to the 1 :125 000 quarter degree sheets. The Division also undertook some investigations in urban areas in order to identify geological features which may affect construction projects. Col/aboration continued with other National Geological Surveys on matters of regional importance and with various university geology departments on specific projects within Botswana. In addition to providing various rock, mineral and other chemical analyses for the various Divisions within the Department, the Chemistry Laboratory undertook Similar work for a number of outside institutions including the pOlice and the Department of Water Affairs. Similarly the Mineral Dressing Laboratory provided thin sections and polished samples to staff within the Department and to a number of outside institutions. A wide range of technical services were also provided by the Laboratory to customers which included the University of Botswana and a number of consulting firms. The Drawing Office continued to prepare all the geological maps produced by the Department for Page 1 printing at the Government Printer. All the diagrams for the Department's publications are also completed in the Drawing Office. The Department's library acquired a number of new technical books as well as receiving a large number of consultancy reports related to work in Botswana. Over 30 international periodicals are regularly received. There were six operational drilling rigs within the Drilling Section although many of these machines are old and need replacing. Nevertheless a number of boreholes were completed on behalf of the various Divisions in various parts of the country. The Department's use of computers has increased steadily over the past few years and all Divisions received new computing equipment during the year. Data processing and handling is increasingly being undertaken on computers. Eventually it is intended that datasets from different Divisions can be merged and analysed using sophisticated techniques such as Geographic Informatiop Systems (GIS). Page 2 5. HYDROGEOLOGY DIVISION 5.1 Introduction The Hydrogeology Division of the Geological Survey Department has the responsibility for investigating and exploring for groundwater r"sources of a regional nature as well as promoting the advancement of applied groundwater research in Botswana. The exploration of groundwater resources involves the assessment of their potential for development and utilisation with water quality being an important factor. The Division also has the responsibility of gathering data on groundwater levels from our established monitoring network, water abstractions, monitoring of water quality evolution and the receival of borehole data and water samples from government as well as privately drilled boreholes. All this information is stored in the National Borehole Records Archive and Groundwater Computer Data Banks as well as in the Drill Sample Store. The National database now contains 15400 records. The research project, Groundwater Recharge Evaluation Study (GRES PHASE 11) was approved and started in November, 1992. This project is being executed as a cooperation research programme between the Geological Survey Department, the University of Botswana and the Free University Amsterdam. Within the Division's internal programmes, limi.ted research continued with the assessment of groundwater resources of Seleka and Kanyenorthern wellfields by Messrs Nkala and Mokokwe who left for Australia early in 1992 to pursue MSc. Hydrogeology programmes. The "Geophysical Methodology Handbook" research project was continued in Canada by G. Shields under the supervision of Professor J. Wright of Memorial University of Newfoundland. This programme is scheduled for completion during the first quarter of 1993. Another research programme was initiated during the year in the Middlepits/Makopong area. This project which is being carried out by our junior hydrogeologist, Mr Molebatsi, investigates hydrochemical and recharge phenomena within the area. Training as usual constituted an important aspect of the Division's activities. Messrs Nkala and Mokokwe left for Australia to pursue their MSc. studies in Hydrogeology at the University of New South Wales. They have now transferred to the University of Technology, Sydney in order to complete their programmes. Mr. Molebatsi left for the United Kingdom in September, 1992 to undertake an MSc. study programme at the University College London. Two junior hydrogeologists, Messrs I. Mabua and M. Magowe, joined the Department on the 1st June, 1992 while a technical trainee, Mr. L. Mutukwa joined the Division on the 29th July, 1992. Mr. J. Marks left the Department on the transfer to Botswana Savings Bank. During the course of the year the Hydrogeology Division continued to suffer from lack of experienced manpower for the planning and implementation of regional groundwater projects. Hence some of the "priority" groundwater exploration projects have been shifted to the Department of Water Affairs for immediate implementation while others still await the recrul.trnent of project hydrogeologists for their planning and implementation. ... 5.2 Development ProJects 5.2.1 Groundwater Studies and Protection 5.2.1.1 Letlhakeng/Botlhapatlou Groundwater Investigation Project Project duration: 15th February, 1990 to