Topographic maps in 1:50,000 scale with contour interval are available for the whole country. 1:100,000 topographical maps with contour interval of 100 meters with French text are also available for the whole country.
French geologists carried out the first geological survey work during 1900 to 1940. The results are included in reports on Indochina and it is not easy to sort out which part of the work was carried out in Laos and which was carried out in Viet Nam.
Scattered geological mapping was carried by geologists from United Kingdom, Bulgaria, Czechoslovakia and the USSR during the 1950's and 1960's.
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In 1966 to 1969 a very detailed United Nations geological survey was carried out in the Vientiane region by Bureau de Recherches Geologiques et Minieres (United Nations reports: 69-RME-058 and 69-RME-41, published October, 1969). The first report describes aero-magnetic investigations and six anomalies discovered west of Vientiane (the future Newmont project). These anomalies were followed up by ground geophysics, geologic mapping and geo-chemical sampling. The mapping was carried out as outcrop mapping. The UN project also included diamond drilling, with detailed rock description including thin sectioning of the core. The second report describes a tin deposit with anomalous contents of lead and bismuth in an area east of Vientiane. Finally, there has been prospecting conducted in Nam Pathene area by French geologists (J. P. Bonnici and G. Sustrac).
After the Lao PDR revolution of 1975, much geological work was conducted in Laos by the Soviet Union, Bulgaria, Czechoslovakia and Viet Nam.
The private mining company, Newmont Vienkham Ltd., carried out detailed work on their MEPA license in an area west of Vientiane, 1993 to 1996 (S. W. Dacies and S. L. Williamson, 1996). Newmont found the sources of the alluvial gold, but considered the sources were too low grade with little significant primary (supergene). Airborne magnetic and radiometric surveys were carried out by helicopter on a total of 19,000 line kilometres, spaced at 200 and 800-meter intervals. Over 3,026 drainage sites were sampled and a total of 4,900 linear meters of diamond drilling was carried out. Newmont relinquished its interest in this property in 1996.
In 1990 United Nations (ESCAP) published an Atlas of mineral resources of the ESCAP region, of which volume 7 covers Lao PDR. The work was carried out by British Geological Survey (BGS). The atlas has a geological map and a mineral resources map both in 1:500.000 scale and an explanatory text. The text has a list of 250 mineral occurrences with their location, mineral commodity, geologic class, age and status of present activity.
In 1990-91 Asian Development Bank published a map entitled: "Lao PDR Geological and Mineral Occurrence Map" at a 1:1,000,000 scale with brief explanatory text printed on the map and an index to mineral occurrences listed by administrative provinces.
During the period 1995-2000 a very detailed geological mapping programmes have been carried out by the INTERGEO division of Department of Geology and Minerals in Viet Nam with assistance from DGM, Laos. (Report Geology and Minerals of mid-central Laos region scale 1:200.000, 1995 to 2000 by Tran van Ban). The survey conducted photo-geological interpretation on aerial photographs and satellite images over a surface area of 29,800 km2. This was followed up by detailed geological mapping covering and area of 3,520 km2. Ground truth surveys were conducted to verify the photo-geological interpretation. Soil samples, which were panned, were collected with a density of 0.24 samples/km2 in selected areas, extensive ground geophysics was carried out, and trenching and hand drilling were conducted. The collected samples were analysed at laboratories in Viet Nam.
A large number of maps were produced by the Lao-Vietnamese project.
For example of the avaiable digital geological maps and geoscientific data produced by the Vietnamese assisted by Lao PDR Department of Geology and Mines in mid-central Lao PDR click here.
Part of the Vietnamese work offers a very detailed description of selected occurrences. All promising gold occurrences have been mapped in 1:10,000 scale and ground geophysics carried out. Geological maps and geophysical profiles are shown together with detailed mineralogy and chemistry. Placer gold deposits were also found, sampled and described.
Click here to view the report on the detailed descriptions of mineral occurrences.
As a result of this survey work 20 promising gold anomalies were discovered by the geo-chemical surveys, examples of which are in the Nam Kata and Nam Pheo areas. Gold particle size averages 0.2 to 0.5 mm locally up to 1.2 mm, associated with pyrite, arsenopyrite, realgar, native lead, cassiterite, scheelite and wolframite. In the Nam Sangou and Nam Sange areas, surveys over 100 km2 found many gold particles. In the same region several cassiterite dispersion haloes were discovered.
The Vietnamese project also produced a special booklet: Record book of mineral deposits and ore occurrences with 153 occurrences of the following minerals: coal, iron, copper, poly-metals, antimony, mercury, tungsten, tin, gold, barite, pyrite, gypsum, rock salt, phosphorite, dolomite, crystalline quartz, ceramic clay, cement limestone, building limestone, cement clay, brick clay, facing stone, roofing stone, gravel, building sandstone as well as thermal water and salt water. Each entry has a number with geographical co-ordinates a number on a map, element, name of deposit, characteristics of the deposit including genesis, stage of investigation and size.
Click here to view the special booklet: Record book of mineral occurrences.
In 2003, a similar project was carried out by INTERGEO division of Department of Geology and Minerals in Viet Nam in North-East Laos with the same detailed approach. There were 60 Viet Nam geologists involved, working in five to six men teams with one Lao geologist from DGM in each team.
The following maps are available in digital form.
· The BGS map.
· The geological and geochemical map from the joint Lao - Vietnamese campaign in central Laos.
· Overview geological map and topographical map.
More specific information on avaible geological maps and other geoscientic data can be obtained by contacting the Lao PDR Department of Geology and Mines by email (dgmnet@laotel.com)
For a descriptive text on these geological maps click here.
Some of the other maps produced by the INTERGEO division of Department of Geology and Minerals in Viet Nam with assistance from DGM, Laos are:
· Tectonic map with legend 1:500,000 scale.
· Geo-morphological maps 1:200,000 scale.
· Geological maps 1:200,000 scale.
· Geologic maps of selected mineral occurrences 1:25,000 sometimes even in 1:10,000 scale.
· Maps of dispersion haloes: Ni, Pb, Sn, Zn, Cu, Co, Cr, Mo and Ba in 1:200,000 scale.
· Maps of mineral resources distribution at 1:200,000 scale.
· Legends for these maps with explanation of symbols, including metallogenic factors, mining status, stage of exploration etc.
