ANNUAL REPORT GEOLOGICAL SURVEY DEPARTMENT 31St
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ANNUAL REPORT of the GEOLOGICAL SURVEY DEPARTMENT for the year ended 31st. DECEMBER 1967 I GENERAL (a) Introduction The Geological Survey Department in the Republic of Botswana, is, for administrative purposes, a "non·integrated" element of the Ministry of Commerce, Industry and Water Affairs, Its headquarters are situated at Lobatsi in southeastern Botswana, 47 miles south of the Botswana Government administrative headquarters at Gaberones. The fundamental aim of the Geolqsical Survey is the assessment of the mineral resour ces and underground water supply resources of Botswana with the intention of stimulating the realisation of their economic potential. A necessary preliminary to the ,attainment of these obj ecti ves is a study of the rocks and the geological structure over the whole of the country. Regional geological mapping and the publication of maps and reports descri· bing the geology of Botswana is thus the main, prime function of the Geological Survey Department. Mineral survey work is carried out and this includes field geological and geophysical survey of mineral occurrences supplemented by laboratory work; prospecting for new mineral deposits; rendering assistance to prospecting organisations and operating mines; and wherever possible furthering interest in Botswana's mineral potential.A third major task of the Geolqsical Survey is the development of underground water supplies and general hydrogeological survey. In underground water development work the Geological Survey carries out the siting of water boreholes after geological and geophysical investi· gational work and then controls drilling of the selected sites to the stage where productive boreholes can be passed to another branch within the Ministry, which is responsible for equipping boreholes and' for the maintenance of Government pumping units. Hydrogeological research work is also carried out and the Geological Survey is gradually building up a considerable body of information about the nature and occurrence of underground water resources in Botswana. In underground water development work, borehole drilling is car ried out by the Drilling Branch section of the Geological Survey, which has its head· quarters at Gaberones and is under the control of the Drill Superintendent who is directly responsible tothe Director of Geological Survey. Besides these main activities, the Geological Survey undertakes special investig3c tions where geological advice is required, such as in certain engineering problems, and also renders assistance to other Goverruncnt Departments whenever required to 'do 80. Special geological and geophysical investigations and research work are also undertaken where they are needed for a better understanding of the basic geology and geological structure of Botswana. The Director of Geolqsical Survey is Mining Commissioner for Botswana and as a result the Geological Survey has certain specific functions to perform in'relation to pros pecting and mining, as well as duties relating to the inspection of mines and machinery, and the implementation of explosives regulations. In addition, the Geological,Survey is responsible to Government for ensuring that mining company prospecting operations in Botswana are carried out energetically and efficiently with due regard to the provisions of the Mines and Minerals Act in force in the country. The main costs of running the Geological Survey and the full costs of development of underground water supplies in Botswana by drilling during 1967 were borne on normal 1 which they are at present mining at their Gopani property in the Transvaal. The company at present operate on claims pegged during a period when they held certain mineral pros pecting rights in the Loliatsi Blook by cession from the mineral right owners, the British South Afdca Company. The main interest in this ore lies in its content of battery-reactive MnO,. 7 •.Tati Territory Exploration Company (Pty.) Limited continued investigations on nickel! copper oocurrences in the Tati District where they are operating in the southeastern part of the area under a notarial prospecting contract held with the mineral right owners, Tati Company Limited. 8. A regional mineral explocation programme was commenced in the privately owned mineral right area of the Tuli Blook by the Anglo American Corporation Limited. 9. State Grants conferring prospecting rights for all minerals over an extensive area of the Ghanzi District Council area and for ·all minerals, excluding diamonds, over an area in the southern part of the North West District Council area, were awarded to Theta Mining and Prospecting Company (Pty.) Limited and Zeta Mining and Prospecting Com pany (Pty.) Limited respectively. Both these companies are subsidiaries of the Anglo Transvaal Consolidated Investment Company Limited. 10. At the end of 1967 applications received from a number of mining companies were under consideration for the grant of special prospecting licences for a variety of minerals, in various areas of Botswana, including precious stones, manganese-ore, brine, talc, gypsum, limestone, other base minerals, semi-precious stones and ornamental building stone. Of considerable importance in the overall sphere of mineral development in Botswana was the enacting dur.ing 1967 of certain legislation relating to mineral ownership and to laws governing mining and prospecting. In underground water development programmes, geological .and geophysical surveys were carried out in all District Council areas. Underground water supplies were developed for District Council and Government requirements, as well as for private individuals, on a repayment basis. During 1967, 117 boreholes (both Government and privately drilled) were completed on sites selected by officers of the Geological Survey. Of these boceholes, 95 Or 81 per cent were successfn!. During the year the Government Drilling Branch worked 00 155 boreholes, .including 19 boreholes which were cleaned and one which was deepe ned. A total of 106 were completed. The total footage drilled was 34.958 feet. Because of the staff position special investigational work had to be confined to. a restricted amount of work on hydrogeological research into underground water resources. (e) Organisation and Starr The Director acted as Permanent Secretary to the Ministry of Commerce, lridustry and Water Affairs for two periods during May to July and again during December. During December C.M.H. Jennings, Deputy Director, acted as Director of Geological Survey.· C.M.H. Jennings, Senior Geologist, was promoted to the post of Deputy Director in January. 4 the parent vents apparently showed a tendency to become blocked resulting in intermittent, but explosive phases of eruptioo. Agglomerates were probably formed in this phase with possibly volcanicdispharges leading to the formation ofignimbrites. Rocks of the Transvaal System' predominate within the Basin Province which occupies arelatively small area between Lobatsi and Ramoutsa. Crockett has suggested thaI many of the structures found within this ,area can best be interpreted as the result of gravity sliding from west to east following collapse of the basin flOor. Four major gravity-slipped masses have been defined. Movement of these, masses was mainly compensated by high- angle thrust faults dipping west. ',' IV, UNDERGROUND, WATER,DEVELOP,MENT (a) Geological Survey Activities The Geological Survey continued to be responsible for the control of all underground water development workin BC(swana. In the course of this work geological arid geophysiCal'surveys were carried out in the Central District Council; North West District Council; North-East District Council; Francistown township; Kgatleng District Council; KwenengDistrictCouncil; Ngwaketse District, Council and SouthEast District Council areas. ' " During 1967, atC(al of 117 completed water boreholes (both Gov.emmentand private) were drilled on sites ,selected after geological and geophysical surveys cacried,out by officersof,the Department, Of these 117 boreholes, 95 were successful representing an overall success value of 81%. This success value is 12.5% higher than that ,achieved during 1966 (67.5%). A tavulated list of bOreholes drilled on sites selected by officers of the Geologica! Survey is given in Appendix V. (b) Drilling Branch Activities During 1967 a record footage of 34,958 feet was drilled by the, Drilling Branoh seotion of the Geological Survey. This total exceeds the footage drilled.in 1966 by 942 feet and that for 1965 by 5,941 feet. Dunngthe ye'ar 155 boreholes (excluding 19 boreholes cleaned and reteSied),were worked oo.O{thistotal of, 155 boreholes, 4 b.oreholes totalliIlg 1 ;554 feet had to ,be,aban doned for technical,reas,ous ; 6, borel\oles totalling l,106,.(eet remained uncompleted at the end of the year;, and (fl,e, bOr"hole was deepened by 111 feet. Forty three boreholes were drilled for purposes other than undergroulld'wateidevelop ment. These:included 7 boreholes totalling 1,52.1 feet drilled on the Sua,pan,jn the Makarikari region for brine pumping tests. Three of ,these boreholesi'totalling 651f8el, were drilled IS-inches in diameter. In addition ,a Halco Tiger cOlnptessed air-operated drilling machine completed 762 feet in 16 bOreholeSdrilled'for'th~ B<\tswane.,Meat Com mission at Lobatsi for foondationtesting purposes and 812 feetin20boreholesdrilled during an examination 6f, ~he Mabelane til.lc occurrence in'i~e Moshanengarea; .. 17 Of the total footage of 31,8.63 ,.feet, drilld in boreholes completed for