SWAZILAND

MINISTRY OF NATURAL RESOURCES

ANNUAL REPORT OF THE

GEOLOGICAL SURVEY AND MINES DEPARTMENT

FOR THE YEAR

1989

PRICE ES.OO

1.

CONTENTS

GENERAL

1.1 1.2 1.3 1.4

Introduction . '" '" .. '" '" .. '" . '" . '" .. '" '" Sal ient points ..••.••. . ••••• staff and Training . '" '" '" .. '" '" . '" .. '" '" . '" '" '" . '" '" '" Technical Cooperation .................... .

2. HEADQUARTERS

2.1 2.2

Administration Staff IO •• '" • '" • '" '"

'" ... '" '" . '" '" .. '" . '" . '" ... '" '" '" . '" '" .. '" . '" '" '" .. '" .. '" '" '" .. '" .. '" . '" '" '" '" .. '" '" '" .

3. GEOLOGICAL SURVEY DIVISION

3.1 3.2 3.3 3.4 3.5

3.6 3.7

3.8

3.9 3.10 3.11 3.12 3.13 3.14

Introduction '". '" . '" . '" '" '" . '" .. '" . '" '" . '" ... '" '" Coal '" '" '" . '" '" '" '" '" . '" .. '" '" '" '" . '" '" '" '" '" '" ... '" .. '" .. DGSM-CIDA Groundwater Project '" . '" '" . '" ... Gold . , ........................ . . ....... . Base and Precious Metals Exploration in Southern swaziland ...................... . Industrial Minerals . '" .. '" . '" '" '" .. '" '" ....... '" Tin-Bearing Pegmatites and their Genetic Relation to the Younger and Older Granitoid Rocks • '" '" '" '" '" '" '" '" . '" '" '" .. '" '" '" . '" • '" '" •••.. '" • '" ••• '" '" • '" The Sinceni and Mhlosheni pluton and their Tin Potential '" '" '" '" . '" .. '" . '" '" '" . '" '" '" .. '" .. '" brilling section ........... . ........•.. Laboratory....... •• Drawing Off ice .•.••• •• Library....... . ... Advisory Services Computer Applications ..................... .

4. MINES DIVISION

4.1 General . . . . . . . . . . ........ . ...... 4.2 Safety and Health ....... . . . . . ...... 4.3 Explosives ........ · ......... . ..... 4.4 Permits and Licences · . 4.5 Mining Employment 4.6 Mines and Quarries ...... · ............... 4.7 Accidents . . . . . . . . . ....... · ...............

5. ACKNOWLEDGEMENTS . ........................... .

Page

1 3 4 8

9 9

10 11 12 26

27 28

30

32 37 38 40 40 40 40

41 41 42 42 42 42 43

44

1.2 S~ENT POINTS

with the publication of the revised 1:250,000 scale Geological Map covering the whole country in 1983 and the 1:50,000 scale Series completed, there is a further need to extend mapping on a larger scale to capture more detail. This activity had been suspended due to the lack of aerial photography at a suitable scale and also in order to concentrate on the economic geology of the Kingdom. In 1989 programmes were conceived to undertake a revision of the 1: 50,000 scale Geology Map Series through the detailed mapping of the country.

The Groundwater Project, jointly run by the Department and CIDA drilled a further 71 boreholes during the year with 76% of these yielding water. Drilling during 1989 was mainly in the west and northwest of Swaziland.

o

A special Exclusive Prospecting Licence was granted by The Ngwenyama to Carbonex (pty.) Ltd. to explore for anthracite coal at Maloma in the southern Lowveld. This represents the first new prospecting licence to be granted within the last few years. If the feasibility study emanating from the exploration work is found to be suitable, Carbonex will then apply for a Mining Lease with a view to begin development work in 1991 and the establishment of Swaziland's second coal mine.

Considerable interest has been shown by the private sector to resume gold exploration in northwestern Swaziland.

The period under review has seen a tremendous surge in the value of mineral production. The ex-mine revenue for asbestos, diamonds and crushed stone all increased by more than 30%, which in the main is a reflection of improved production in the relevant enterprises with a slight upturn in commodity prices. The production of coal at Emaswati increased slightly but commanded a significantly better price.

Mineral revenue for the year represents an increase of E43,566,999.

3

amounted to E56,190,879 which 29% on the 1988 figure of

3.3 DGSM-CIDA GROUNDWATER PROJECT

Executive Summary

The Groundwater Exploration Programme entered into its fourth year of operation in 1989. The project's goals remain unchanged. There are two main activities:

* detailed field investigation to iden~ify hydrogeological characteristics of Swaziland's var~ous geologic units, which includes collection of existing data, surface geophysical surveys, aquifer tests and drilling new boreholes;

* an intensive office programme which is map oriented; information is presented in terms of identifiable hydrogeological units, borehole yields, and anticipated water chemistry.

Field work is carried out both to collect data from existing sources and to gather new information and evaluate geological formations by means of drilling and testing. The technicians are proficient in the operation of pump tests, borehole monitoring, surface geophysics and rig supervision.

The data reporting format has been developed with input from potential users such as the Rural water Supply Board, and various other agencies concerned with surface and ground water supply. The first two Hydrogeological Reconnaissance Maps were completed in 1987, ten more in 1988 (4 of which are partial sheets along the Mozambique border), and six in 1989. This leaves a total of 12 maps to complete in 1990, of which the area covered by two have been drilled and require only final drafting, while no holes are to be drilled on a third sheet because of remoteness. The emphasis during 1989 was to improve the accuracy of borehole locations, and to evaluate different methods of data presentation.

12

3.3.1 Introduction

This is the fourth annual report for the eIDA/Swaziland Groundwater Survey project and covers the period of activity from January I, 1989 to December 31, 1989. This represents the fourth year that the project has been in operation.

The project is a bilateral agreement between the Governments of Canada and Swaziland and was designed to meet the following:

* to evaluate and determine the groundwater quality and quantity in Swaziland, with emphasis on the Lowveld,

* to set up a suitable infrastructure within the Department of Geological surveys and Mines to effectively carryon the groundwater investigation at the completion of the five year project, and

* to help formulate regulations concerning the Kingdom's water resources through the incorporation of a National water Authority.

During 1986 the project was primarily involved with the first two goals, while development of Draft Legislation for the National water Authority began in 1987. The Project's three specific goals in 1989 were :

* data collection and evaluation with the focus on data collection through drilling and testing of boreholes located in the Middleveld and Highveld, as well as incorporation of all existing groundwater information into the project's computer data base,

* continued on-the-job training of the Department of Geological Surveys and Mines staff attached to the project, as well as formal training at a local technical college,

* data analysis, technical map preparation, and checking accuracy of all data.

The manner of data collection and borehole site selection in 1989 is unchanged from that summarized in the 1986-88 triennial report.

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3.3.2 Data Collection

Background

In order to effectively evaluate the groundwater resources of Swaziland it is necessary to develop a firm data base of hydrogeological information. Two sources of information have been identified for this project which include:

* all existing borehole/spring data with information from Rural water supply Board (RWSB) and other sources,and

* data generated from field operations of this project which include data from geophysics, drilling, testing and chemical water quality analyses.

Existing hydrogeological data has been collected from most sources in swaziland. Records from the RWSB, in particular, have been most helpful. Other sources of information include:

* Council of Swaziland Churches, * Emanti Esive, * Near East Foundation, * water and sewerage Board, * Lutheran World Federation, * Swaziland Railway, * local drillers, * private borehole owners.

Existing groundwater data in general, and borehole information, in particular, in the past has not been collected in a systematic manner. Existing borehole data is u~ually only of limited value, often only providing information on hole depth and possibly blown yield. In addition, the locations of existing boreholes. are often difficult to establish with certainty.

Existing borehole information is used to assess the areas where groundwater exploration and drilling is needed. Field work, including drilling, is carried out to either verify observations from the existing data or to provide informa­tion where none exists.

Borehole site Selection

Collection of data begins in the office where data deficiencies are summarized and the approximate locations of boreholes to be drilled are identified. proposed boreholes are generally sited where there is a lack of technical information, and/or to evaluate a specific geologic unit or feature. Consideration is given to locating boreholes at or close to areas of water need, and many project boreholes are put into use at a later time.

14

Groundwater in swaziland generally occurs in areas of fracture and other secondary permeabili ty, usually associated with tensional features such as fault zones, geological contacts, (including chilled zones at dyke and sill contacts) , fracturing and jointing, zones of brecciation, or brittle, well fractured rocks such as quartzi tes, etc. Other important aquifers are weathered zones and alluvial materials. Surface discharge features, or geophysical anomalies may be indicative of relatively high yielding aquifers. Accurate location of permeable zones can be very difficult to determine in the field. Various mapping and investigative procedures are used to locate these zones, including:

* geological mapping, * 1:5,000 scale ortho-photo mosaics, * interpretation of aerial photographs, * on-site field inspections, * identification of surface discharge features, * surface geophysics, including electromagnetic,

resistivity, and magnetometer surveys.

The selection of specific borehole sites in the field is based on several factors, including:

* presence of significant hydrogeological features as mentioned above, other high yielding boreholes in the vicinity, surface discharge features (seep or favourable zone of weathering identified through techniques listed above), favourable lithology,

* the need for additional lithological data in a specific area,

* accessibility of the site by drilling rig equipment,

* land ownership, and * areas where water is needed.

Technical supervision of all field activities relating to the borehole, including drilling and testing, is the responsibility of the CIDA and Department of Geological Surveys and Mines field hydrogeologists. swazi field technicians handle all aspects of the field work, including geophysical surveys, aquifer testing, spring and borehole surveys, borehole monitoring and sampling.

3.3.3 Field Programmes

summary of Field Activities

Field· activities in 1989 were conducted until mid-August from Camp 4, located on map sheet 7 on a government farm 3/4 kms. east of Madlangampisi. Work for the remainder of the year was from Camp 5 in the Ntondozi area on map sheet 17.

15

A total of 71 boreholes were drilled and completed, 32 pumping tests conducted, and 150 geophysical survey traverses run during the year on map sheets 2, 3, 5, 6, 7, 10, 11, 12, 13, 17 and 18. The quarterly breakdown of drilling tests and surveys is as shown in Table 3.3.1 below:

Table 3.3.1 Drilling Tests and Surveys

Quarter #Boreholes

1st Quarter 16 2nd Quarter 20 3rd Quarter 12 4th Quarter 23

#Pumping tests

7 9 7 9

#Geophysics surveys

19 85 43

3

A detailed list of boreholes, pumping test and geophysical survey data are on file in the Groundwater Project Office.

More emphasis was placed this year on work in cooperation with other agencies. As a result, some time, notably by Obed Ngwenya and Aaron Vilakati, has been spent in siting boreholes for individuals, Government departments and private organizations. As an example, 22 boreholes were sited for Emanti Esive in the Ngcampha1ala area on map sheet 26. This has resul ted in the proj ect gaining valuable borehole information with a minimum of expense, the fostering of good working relationships with others in a spirit of cooperation, and the gaining of first-hand knowledge of the method of operation of local drillers. Other examples have been on a smaller scale, in which only one to a few boreholes have been sited.

A greater emphasis was placed this year on gathering hydrolgeological data from existing boreholes and springs, while the need for more accurate location of boreholes became apparent. The given co-ordinates of existing boreholes were consequently checked for accuracy, while the existing method of recording and reporting borehole locations was revamped to include a more thorough system of checks in order to eliminate errors.

Project vehicles

Three new Toyota Land Cruisers were received during the year to replace three Land Rovers which were in bad condition, and which were turned over to the Central Transit Authority (CTA) .

A new engine was installed in drill rig No.1. The old engine was overhauled and will be kept for a spare.

16

Drilling Program

Work schedule

The field camp operates on a ten day shift, four days off work schedule including two working days. Exceptions occur during public holidays and occasionally at the end of the month when a short shift may be necessary to allow the field crews sufficient time to receive and deposit their monthly pay cheques. The field operations continue throughout the year, with a four week break from· mid-December to mid­January.

Drilling Activity

A total of 71 boreholes were drilled in 1989, mostly completed open-hole, with surface casing used to case off the loose material of the weathered zone, although some of the boreholes required installation of slotted PVC liners in order to prevent caving of the open hole. A summary of the amount of drilling per calendar quarter is shown in Table 3.3.2, below.

Table 3.3.2 1989 Drilling summaries

Quarter (Calendar)

Boreholes Drilled

1st Quarter 16

2nd Quarter 20

3rd Quarter 12

4th Quarter 23

Total 75

Total Depth

(m)

Range in Aver_ Depth Depth

(m) (m)

Borehole Yield Totel Range Aver_ (lIs) (l/a) (lIs)

1288 7 • 120 80.5 16.9 .01· 4.0 1.1

1502 21· 137 75.1 46.5 .01 ·10.0 2.3

1116 61· 103 93.0 21.7 .01·4.0 1.8

1734 17· 92 75.4 79.7 .01 ·20.0 3.5

5640 7 • 137 79.4 164.8 .01 ·20.0 2.3

Boreholes drilled in 1989 averaged 79.4 m in dep~h. Airlifted groundwater yields were highly variable, rang~ng from "dry" to 20 Lis (litres per second). A total of 17 dry holes were drilled in 1989 (ie. holes with yield of less than .01 Lis), for a successful completion percentage of 76%. This is a higher percentage of success than in any of the previous years, and is attributed to most of the drilling taking place in the highveld which is an area of high rainfall and recharge to the aquifers. The greatest number of dry holes were drilled in granite (7), gneiss (4), and diabase and schist (2 each).

Total metres and number of boreholes drilled per calendar quarter from the beginning of the proj ect is shown on Fig.3.3.1, on page 19. The greater meterage obtained in the early part of the project (1986), is believed to be due almost entirely to very close well spacing in many areas,

17

with resultant less time lost during rig movements. This concept was changed in mid-1987 to allow for a more widely scattered, but more even spacing of boreholes throughout the kingdom of swaziland over the five year life of the project.

Aquifer Testing and Borehole Yields

Thirty two aquifer tests were carried out during the past year. The tests usually involve pumping a single production borehole for a period of 24 hours, while water level recovery is generally only measured for a few hours. Twenty two tests were for 24 hours of pumping time, one test was for 51 hours, and the others were for lesser time periods, due mainly to excessive drawdown during the tests,or to generator problems. No sites with observation boreholes were aquifer tested in 1989.

Aquifer test data is used to calculate aquifer transmissivity and, where an observation well is used, storativity. This quantitative information can be used to determine long term well yield, and total yield and correlation of different aquifers.

A total of 59% of the successful boreholes were pump-tested (32 of 54 boreholes). An analysis of aquifer test results compared to airlifted borehole yields has not yet been done. The well yields shown on the hydrogeological maps are airlift yields, which are obviously short-term borehole yields. Analysis of aquifer tests will give theoretical long term yield values.

water Level Monitoring Programme

This programme has been significantly altered since 1986. As the number of boreholes increased, the number of holes moni tared also increased and became extremely time consuming. Analysis of the data showed that water level fluctuations were minimal in lowland areas. It was therefore decided that only selected boreholes would be monitored in future. These were selected on the basis of:

* representation of different geological settings, * frequency of previous measurements, and * the ease of access to an all-weather road.

Thirty-one boreholes were being monitored on a monthly basis at the end of the year. This is an increase of eleven from 1988. The hydrographs from each of these are generated using the project's personal computer and are updated each month. Automatic water level recorders are currently being tested for suitability for long-term monitoring.

18

30 .

28

'" 26 l-~ 24

. f-

<I :::>

22 a r- l-

'" w 20 n- I- l- f--o 18 j ii: 16

l- I- l- I- l-

I- l- I-- l- I-0

14

"' l- I- l- f- f- f- l- I-

~ 0

12 l- I- l- f- f- f- f- f- f- l-

" w 10 '"

I- l- I- f- f- f- f- f- f- l- I- l- I- l-0

'" 8 I- l- I- e- - l- I- l- I- l- I- - - i- -6 - l- I- I-- - I- - - I- - - - - - -4 - l- I- I- - I- - - I- - - - - - I--

2 - I- '- '- - I- - I- '- '- - - - - r-0

1986 1987 1988 1989 YEAR (by quarter)

3

2.8

2.6 l-

2.4 I-

2.2

'" l- I-

w Ii: 2 l- I-<I ::> 1.8 a l- I-"'-;; I.e W'O o.c

l- I-

~:l 1.4 ,Ji: 1.2 iiF' 0-

~

- - - - -- - l- I- - - - - I-

- - f.- I- - l- I- - - f-- l- I--

~ 0.8 l- I- - l- I- l- I- l- I- l- f- -;,; 0.6 l- I- - l- I- - l- I- f- - I-- - f- -

0.4 l- I- l- I- - I- - l- I- f- - I-- - - -0.2 l- I- l- I- l- I- I-- l- I- i- l- I- '- '-- I-

0 1986 1987 1988 1989

YEAR (by quarler)

FIGURE 3.3.1

SUMMARY OF QUARTERLY DRILLING STATISTICS

19

Hydrochemical Programme

One hundred and sixty two chemical analyses were carried out in 1989 at the DGSM laboratory in Mbabane.

The project has a portable sampling pump and a small pump hoist, built in 1988, to assist in collecting water samples.

Geophysical Investigations

Surface geophysical investigations playa major role in the field siting of boreholes. Electro-magnetic induction, resisti vi ty, and magnetometry are the three main methods employed.

Geophysical surveys are run at many proposed borehole sites, where surface expression of favourable hydrogeological characteristics is not evident. The geophysical surveys can increase the likelihood of encountering fractures, faults, etc.; however, they do not guarantee that a suitable aquifer will be encountered by the borehole. Faults in the Karoo sediments, for example usually prove to be dry.

Surface geophysics are essential to maximize borehole yields in most hydrogeological units and have been found to be most helpful. The likelihood of drilling high yielding boreholes (>2 Lis) in lowveld areas is substantially increased by the use of geophysical surveys. A software programme to help analyze surface resistivity data was purchased in 1988. The project will receive a field computer in January 1990, to aid in processing and interpretation of geophysical data in the field. All field technicians and technical assistants will be trained in computerized geophysical data processing once the new equipment is received.

A review of the project's geophysical methods was carried out by an outside consultant in 1989, whose final report is scheduled to be completed early in 1990.

3.3.4 Data Compilation and Analysis

Field Activities

Field data files are initiated in the all the hydrogeological information individual borehole. Most borehole following information:

field and summarize pertaining to an

files contain the

1.Borehole Summary Report : this is a single page report which summarizes all technical information, as well as pre-siting criteria for each borehole.

2.Summary of Geophysics (if carried out); this is usually in the form of a profile which highlights anomalous areas. This information helps in the siting of boreholes to optimize water yield, as well as to determine the

20

effectiveness of the various geophysical instrumentation.

3.Driller's and hydrogeological logs; the driller's report is prepared daily and summarizes all the important observations during drilling. These reports are used along with the technician's/hydrogeologist's field log to prepare accurate hydrogeological logs. The field logs form the basis for data analysis in the office.

4.pu~p Test Result (if carried out); in the observations of water level vs. time and pumping rate are presented in this section. The rough field data is usually attached as well as the field station prepared copies; these good copies are necessary to avoid the computer operator having to rewrite and edit data prior to data entry. A copy of the drawdown graph(s) prepared by the responsible field technician may also be included.

5.Field Water Chemistry ; a summary of the field values of temperature, pH and electrical conductivity is included in this section.

6. si te sketch and location plot on orthophoto ; the technician in charge or hydrogeologist must prepare a site sketch showing all pertinent geographical and hydrogeological features, and must show the borehole location on an orthophoto.

Once the field data files are properly completed they are then sent to the project office in Mbabane for final review and checking prior to input into the computer data base. The original field data is also retained in a paper file.

Data Entry, Processing and Analysis

The proj ect 's Hewlett Packard computer allows relatively rapid input of all collected data into the main borehole/spring data base. The data base computer is operated by highly skilled and motivated DGSM technicians. Once the data has been entered into the main computer ,data base, it becomes more readily accessible for further statistical assessment and manipulation. For example, a plot of borehole locations or a profile in a certain area can be run off in less than an hour. This processed data can then be examined by the hydrogeologists and technical observations can be made.

Hydrogeological Maps

The concept of the technical reports envisaged at the beginning of this project was changed in 1987 to one of Reconnaissance Hydrogeological Maps. Preliminary copies of map sheets 26 & 31 were released in 1987. Sheets 9, 13, 14, 15, 19, 20, 21/27, 25, and 30 were completed in 1988, and sheets 2, 3, 6, 7, and 4/8 in 1989.

21

All maps include marginal notes, and side maps showing water quality and physiography along with isohyets of annual precipitation. A summary table of major aquifer unit characteristics, and a bar graph of water quality are also included.

3.3.5 Training Programme

The training was changed considerably during the second half of 1987. In 1986 and the first half of 1987 the majority of the training involved lecture-type presentation of formal courses, often consisting of several different modules. These courses offered relatively technical information dealing with the theoretical aspects of hydrogeology and field investigations in general.

In the last half of 1987, the formal lectures were reduced considerably in favour of more individual, on-the-job training with particular emphasis on applied hydrogeology and r.esponsibility. To this end, all technicians are expected to be able to handle all field duties, which include aquifer testing, water sampling, geophysics, borehole and spring surveys, maintenance of field equipment, borehole logging and siting.

with the departure of Doug Watt in June, 1989, Eric Dlamini assumed the responsibility for the maintenance and supply of the field camp, drill rigs, and vehicles.

An exchange program with Swaziland College of Technology ( SCOT), saw three technicians from the proj ect (Simanga Ngubane, Zephania Methula, and Victoria Dlamini) attending a one year water technicians course at SCOT in 1989, in exchange for two SCOT students (Richard Ginindza and Musa Ndwandwe), who worked as field technicians in the project in order to gain practical experience.

The progress of technicians is monitored by personal interviews and discussions, review of field reports, and the presentation of the data collected. In the office, emphasis is placed on the input of collected data into the project's computer database using both the HP and IBM computers. Tom Mkonta and Pinkie Mazibuko have continued to be trained on both the HP system as well as the IBM computers. Charles Mhlanga and Jerry Wagner - Watchel were added to the team in the past year, and have added to the computer expertise available in the office.

Two project technicians, Zephania Methula and Pinkie Mazibuko, left at the end of the year for two year diploma courses at the Northern Alberta Institute of Technology (NAIT), leading to a diploma in Geosciences Technology (Groundwater Technology option).

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3.3.6 Preliminary Conclusions

In the previous year of this project, several important hydrogeological interpretations and conclusions were drawn. The following observations were noted in 1987 :

1. The EM-34 electromagnetic induction equipment is very effective in the delineation of shallow fault zones.

2. Basaltic aquifers may exhibit relatively high transmissivity in topographically low areas or along baked contacts of dolerite intrusions. Boreholes located in high regions tend to be very low yielding or dry.

3. Short-term borehole yields of up to 6 Lis are possible in selected areas of the Lowveld.

4. Groundwater in the Lowveld is brackish as was previously considered. into basal ts occasionally encounter relatively high amounts of nitrate.

generally not as Boreholes drilled water containing

5. Coarse grained doleri te sills or dykes may form aquifers when highly weathered along their contact zone or along the dyke or sill itself.

6. Fault zones form aquifers, and SW-NE trending faults (i.e. across the strike of most structures) tend to be most transmissive. Dyke breccias form good aquifers.

7. Dolerite inliers, located in the basalts, are usually good aquifers and capable of sustaining domestic demands. Dolerite inliers in the Karoo, however, are generally not suitable for groundwater development.

8. Dry holes are very common in Karoo sediments. Both dolerite inliers and fault zones within the Karoo have generally failed to yield any measurable amount of water, although the "baked contacts" along the margins of the dolerite dykes form reasonable aquifers.

9. A prolific aquifer, the Manyonyaeni Aquifer in the Southern Lowveld, consists of deeply weathered basalts, and covers a large area in which boreholes may be sited without advanced siting technique.

Additional observations, and modifications to the above, made in 1988 were as follows:

1. Good well yields were noted in the upper part of the Karoo sediments (i.e. in the sandstones of the Nkondolo Group) on map sheets 4 & 8. Yields of up to 1 to 4 Lis and occasionally higher yields have been obtained.

2. Screened boreholes completed in alluvium were drilled in 1988 along the Komati River and elsewhere.

23

3. Limited drilling in the Lebombo rhyolites has met with generally poor success, although fracturing in the area north of siteki seems to be more extensive than to the south as shown by only a 50% drilling success rate in the south, as opposed to a 75% to 90% success in the north.

4. A major fault zone over a length of 10 kms. which passes through siteki, provides a good yielding aquifer within the Lebombo Rhyolites and the Sabie River Basalts.

5. Deeply weathered basalts have not been found north of Siteki.

6. Leucocratic gneisses inter layered with amphiboli tic bands and cut by pegmatite veins form excellent aquifers and can yield up to 12 L/s.

Additional observations made in 1989 were as follows :

1. Drilling to date in the Greenstone belt has indicated yields of up to 5 L/s, with a low frequency of "dry" holes.

2. A regional fault zone on sheet 12 has yielded as much as 20 L/s to a single borehole, the highest yield yet obtained during this project.

3. Granodioritic gneisses on sheet 12 have been consistently high-yielding, averaging almost 2 L/s. This increases almost threefold where the granodiorites are interlayered with amphibolites or serpentinites, or cut by dolerite, diorite, or pegmatite dykes or veins.

The preparation of Hydrogeological Reconnaissance Maps continued in 1989.

preliminary copies of Map Sheets 2, 3, 6, 7, 4/8, 9, 13, 14, 15, 19, 20, 21/27, 25, 26, 30, and 31 are available at the Department of Geological Surveys and Mines, Mbabane. The maps are being used by the RWSB and other water users. Work commenced in 1989 to improve the accuracy of borehole locations, both in the field and on the final maps. Some changes in the method of presentation are currently being tried in an effort to show more hydrogeological detail on the maps, and to better conform with international standards.

Drilling during 1989 was mainly on map sheets 2, 3, 5, 6, 7, 11, 12, and 17.

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3 .. 3 • 7 Closure

The Groundwater Evaluation Project completed its fourth year of operation on as positive a note as in previous years. The entire project team of both the Department of Geological Surveys and Mines and piteau Associates works together in a cooperative manner. Each and every member of the team knows their respective tasks and delivers the requirements of the job with enthusiasm and diligence. With this togetherness of purpose firmly sustained, the success of the project has never been in doubt.

25

3.9 DRILLING SECTION

3.9.1 Introduction

The Drilling section operates a number of drilling rigs and provides a service to the Hydrogeological and Geological sections in the Department as well as to the other Government Departments on request.

In 1989 the sections efforts were concentrated on the joint swaziland/Canadian and UNDP water Drilling Programmes covering the entire country. However, it was also possible to increase the coal exploration drilling for Emaswati at Mpaka.

3.9.2 Mpaka Coal Drilling

At the beginning of the year the drilling rigs and their auxiliaries were repaired and serviced by Precision Diesel Electric and Hytec while the drill crews, drillers and technicians were reconstructing camps and replacing old rondavels with steel ones.

Drilling resumed in July for the Emaswati Colliery. Two YBM rigs started the drilling programme but due to a major breakdown a private drilling company was later hired to drill some of the boreholes.

3.9.3 water

The Halco 230 rig continued drilling water wells on request for the Rural water Supply Board throughout the country, although its performance was severely affected by the frequent air compressor breakdowns.

Water wells

Coal exploration

37

1988 (m) 267

671

1989 (m) 456

1583

3.10 LABORATORY

3.10.1 Introduction

The Departmental Laboratory provides services in chemical analysis and preparation of thin sections of rocks for microscopic examination. These services chiefly are used within the Department. During 1989, the Laboratory's analytical services also were used on a non-commercial basis by the Police Force, the Army, the Rural water Supply Board, the Mining Industry and interested members of the public. As well as providing services, the Laboratory also undertook the preparation and standardization of "IN-HOUSE" reference materials to be used for quality control. During the year, 1488 samples distributed between fifty batches were received for attention. A list of jobs undertaken during the year is presented in Appendix III.

3.10.2 Police Department

During the year, the Royal Swaziland Police Force submitted various Court Exhibits for analysis or identification. Among them were samples of gold ore, gold/silver bullion and semi-precious garnets.

3.10.3 Groundwater

Two hundred and three samples were received from the Canadian sponsored groundwater exploration project. On a routine basis, pH and electrical conductivity were measured and the samples were analyzed for six cationic and five anionic constituents. During the year, several improvements were made in this service. Among these improvements may be mentioned the institution of the use of control solutions for monitoring analysis and the titration of alkalinity to a potentiometric end-point replacing use of colour indicators.

Fifty four samples were submitted by the Rural water Supply Board. In most cases, analysis for fluoride was the only service required.

3.10.4 Geochemical Exploration

In this field, the Department was active in the regions of Ntfonjeni and Mahlangatsha. The Laboratory received pan concentrates and samples of hard rock, sifted stream sediment and sifted soil submitted for rapid semi-quantitative analysis of trace elements, more especially gold. Thin sections for microscopic examination were prepared from some of the hard rock specimens.

38

APPENDIX V

PLANS AND DRAWINGS PRODUCED

NO. TrTLE SCALE

1844 Labour Administrative 1:250,000 Areas

1845 Reconnaissance Hydro- 1:500,000 geological Sheets 4&8

1846 Geologists & Engineers of the Department

1847 Geological & Engineering Technicians in Training

1848 prospecting Areas in 1:250,000 N.W. Swaziland (a,b)

1849 Reconnaissance Hydro- 1:500,000 geological Sheet 7

1850 Map of Intsakana Dolerite

1851 Source of Reference Material at Lomati Mine

1852 Reconnaissance Hydro- 1:500,000 geological Sheet 3

1853 Geological Laboratory Techniques

1854 Type Deposits

1855 Geology of part of Mah- 1:10,000 langatsha S.W. Swaziland

1856 Distribution of Mpuluzi 1:500,000 Granitoid Phases

1857 Distribution of Mafic 1:50,000 Dykes

1858 Tonkwane Pegmatite (B)

1859 Reconnaissance Hydro- 1:500,000 geological Sheet 6

1860 Reconnaissance Hydro- 1:500,000 geological Sheet 6

54

AUTHOR DATE

Labour Feb.' 89 Dept. CIDA Feb. '89

A.M.V. Feb. '89

A.M.V. Feb. '89

W. B. Mar. '89

eIDA Jun. '89

B.P. Jul. '89

M.J.M. Jul.'89

erDA Jul. '89

Lab. Aug. '89

M.J.M. Aug. '89

L.K. sep. '89

R.M.M. Sep. '89

R.M.M. sep. '89

R.M.M. Sep. '89

CrDA Oct. '89

erDA Nov. '89