International Atomic Energy Agency IUREP N.P.S. No. 109 November 1977 Distr. LIMITED Original: ENGLISH

INTERNATIONAL URANIUM RESOURCES EVALUATION PROJECT

IUREP

NATIONAL FAVOURABILITY STUDIES

LAOS

77-1006?

INTERNATIONAL URANIUM RESOURCES EVALUATION PROJECT

I U R E P

NATIONAL FAVOURABILITY STUDIES

IUREP N.F.S. No. 109

LAOS

CONTENTS

SUMMARY PAGE

A» INTRODUCTIONAAND GENERAL GEOGRAPHY" l'

B. GEOLOGY OP LAOS IN RELATION TO POTENTIALLY FAVOURABLE URANIUM BEARING AREAS

C. PAST EXPLORATION 2.

D. URANIUM OCCURRENCES AND RESOURCES 2«

E. PRESENT STATUS OP EXPLORATION 3-

P. POTENTIAL FOR NEW DISCOVERIES 3.

BIBLIOGRAPHY 4.

FIGURES No. 1 MAP OF SOUTH EAST ASIA

SUMMARY

Laos is a land locked country containing about 3.5 million people living primarily at a subsistance level. Geologically, the country contains a few places that may be marginally favourable for uranium deposits. A uranium potential in the upper half of Category 1 is assigned.

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A. IHTRODUCTION AND GENERAL GEOGRAPHY

Geography

Laos is a country of about 236,800 square kilometers. It is land locked brodering China, Vietnam, Cambodia, Thailand and Burma. Slightly smaller than West Germany it is mostly mountainous with only a small portion near the Mekong River being fertile. The Mekong River forms boundaries with Burma, Thailand, and Cambodia.

Most of the country's 3,500,000 people are ctncentrated in the extreme southwest portion along the flood plain of the Mekong River. These people tend to a village type of culture while the other third who are "hill tribes" tend to a tribal type of culture. The first cultivate the fertile Mekong flood plain and Bolovens Plateau, the only other fertile area in a permanent repeating fashion, while the hill people use the slash-and-burn-move-on type cultivation.

The landscape in Laos is dominated by the jingle covered mount- ains. In the north jagged crests reach 2400 meters but in the south elevation range in the order of 1350 meters. The south part of the country takes as its border the Vietnam the Chaine Annamitique (Annamese Cordillera), while the north is a tangle of ranges term- inating the Himalayas.

Climate

The climate of Laos is largely determined by the monsoons from May to October off the Gulf of Thailand. Over most of the country rainfall is heavy, about 180 cm, but seasonal. Temperatures range from cold season lows of (l6° to 21° C) to the 32°Cfs just before the rains.

Access

The Mekong and its left-bank tributaries form the principal artery of transport, although the size of craft is limited by rapids and traffic is seasonal. There are no railways in Laos. A road/rail project, linking Vientiane with Bangkok and sponsored by the Mekong River Development Project, is under survey. In September 1976 an official communique confirmed that studies would be undertaken for the construction of a railway link between Laos and Viet-Ham. In 1971 there were about 6,500 km of roads, of which about 12 per cent were sealed. A new road from Vientiane to Luang Prabang has been built. There are six airfields for internal and one for international services. There are no seaports. - 2 -

Industry and currency

The principal industry of Laos seems to be agriculture at the subsistance level. By 1973 the timber exports were the most valuable product, being worth over twice as much as the next most important - tin, which is also practically the only mineral product of Laos. There appears to be no geological survey or other government agency concerned with geologic studies«

The unit of currency is the kip, and $US loOO = 200 new kip.

B. GEOLOGY OF LAOS IN RELATION TO POTENTIALLY FAVOURABLE URANIUM BEARING .AREAS

Laos is a generally mountainous country, in the general form of a hatchet: the "head" consists of complex sandstone and limestone plateaus deeply etched by rivers in forbidding gorges, with the major valleys focusing on Luang Prabang| the "handle" is part of the hill country west of the Annamese Cordillera (Chaine Annamitique) watershed, from which short streams drain westward into the Mekong (qv). This great, fast-moving river, has major rapids caused by distorted strata from the Annamese chain formations.

The Chaines Annamitique represent the last of the three orogenic pulses of the Indochina Peninsula. Intrusive and largely pyroclastic extrusives cut and cover marine Mesozoic sediments. Both granite and metamorphics of varying grade are present.

The southern end of the ;'handle" of Laos is predominantly Indosinias of Triassic Jurassic-Cretaceous ages. In some areas the under lying carboniferous-Triassic volcanic rocks are exposed and in others quaternary basalts appear to have formed lava flows over the Indosinias.

Further north along the "handle" and into the "head" of Laos, Paleozoic and Mesozoic sediments and metamorphic rocks appear to have been intruded by or overly a paleozoic granite or granodiorite.

Some localized Precambrian schists may have been mineralized by the Paleozoic granite intrusives.

C. PAST EXPLORATION

It is doubtful if any- uranium exploration has ever been carried out in Laos.

D« URANIUM OCCURRENCES AND RESOURCES

There are no known uranium occurrences, and no uranium resources in any category has ever been reported. - 3 -

E. PRESEM1 STATUS OF EXPLORATION

There is no known uranium exploration programme of any kind being planned or carried out in Laos. ;

*"• POTENTIAL FOR NEW DISCOVERIES

Generally, except for tin, there are no mineral products in Laos. Geologically, it appears that uranium deposits might be found, principally in a Pre-Cambrian metamorphics but probably in quite limited quantities - perhaps insignificant quantities. But because of what appears to be marginally favourable geologic con- ditions, a.uranium potential in upper half of Category 1 (0-1000 tonnes ll) is assigned.

Compiled by M V Hans en & J Bowman November 1977 IAEA ' • ' Vienna - 4 -

BIBLIOGRAPHY"

1. World Almanac and Book of Facts, 1977, Newspaper Enterprises Association, Inc., New York

2o Encyclopedia Britannica, 30 Vol.,, 15th Edition, 1974 Encyclopedia Britannica Publishers, New York

3. National Geographic Society, Map, 1967, Scale 1:1,900,800 Vietnam, Cambodia, Laos and Thailand and Adjacent Archipelagoes

4« Van Bremmelen, W.B., The Geology of Indonesia, 3 Vol., 2nd Edition, 1970, Martinus Nijhoff Inc., The Hague

5. Weeks, Lewis Go, 1959, Geologic Architecture of the Gircum-Pacific American Association of Geologists Bulletin, Vol. 43, No. 2

6. Carte Ge"ologique de l'Asia et D 1'Extreme - Orient - 1:5,000,000, Published 1972 by UNESCO, Paris, with exploration (in French)

7« Encyclopedia of Nations

8, Europa Yearbook 1977, Vol 11 MAP OF SOUTH EAST ASIA