By THAN HTUN (GEOSCIENCE MYANMAR)
EPISODE: 62
JADEITE FROM BURMA
This article is a continuation of Episode 61, featuring jadeite from Burma, contributed by HL Chhibber in 1934.
1.Outcrop Mines
(b) The Mienmaw dyke
On the Mienmaw dyke are situated the outcrop of Shammonmaw (25° 43’39”, 96° 20’ 40”), Mienmaw (25° 43’ 24”, 96° 20’40”) and Sharoinawngmaw (25° 44’59”, 96° 29’40”). The two extreme outcrops are separated by a distance of 1.5 miles in a north-south direction.
Shammonmaw: The outcrop of Shammonmaw is marked by two old workings aligned in a north-south direction. The northern one is bigger and is 70 feet long, 30 feet wide, and 25 feet deep and was filled with water at the time of the author’s visit. Mienmaw: The important locality of Meinmaw has been worked on spasmodically by several people. There is a heavy overburden of red earth with abundant iron concretions, 25-30 feet in thickness, but nothing about the relationships of the rocks of the dyke could be seen since the old workings have been filled up with red earth washed from above; only serpentine and chloritic schist (byindone) could be seen in places. In one place chromite-epidote was observed with albitite (“palun”) and this is a favourable indication of the occurrence of green jadeite in the vicinity: chrome epidote is formed where chromite is present in serpentine, and the associated minerals, albite and jadeite, are coloured green as a result of absorption of the epidote.
Sharoinawng-maw: The workings of Sharoinawng-maw lie deserted now, though a Chinaman from Hmawlu, near Zeba, worked it for two years some times ago and employed 50 to 60 coolies both here and at Wikhomaw. After he died in China, the work had to be abandoned.
(c) The Pangmaw dyke
The third dyke with a N W-S E extension for a little over three-quarters of a mile comprises the outcrops of Pangmaw, Wikhomaw and Kyobatmaw.
Pangmaw: The old workings known as Pangmaw are found 80 paces N E of the Pang hka, where it is crossed by the Namshamaw-Mienmaw path, where ten small deserted pits are to be seen. Jadeite and albite are both found here with inclusions of amphibole. The serpentine is rendered fibrous near the contact and occurs as detached boulders around the pits. In the neighbourhood of the jadeite workings, chromite and iron ore boulders also occur in a small water course.
Wikhomaw: About half a mile N W of Pangmaw, 13 old pits are to be seen, which mark the jadeite outcrop of Wikhomaw. The biggest pit, which is really a combination of three smaller ones, is about 60 feet in length in a north-north-east-south-south-west direction. The breadth of the work is 32 feet. At the top, there is an overburden of red earth about 6 feet in thickness. It is underlain by schistose and serpentine.
Kyobat-maw: The old workings of Kyobat-maw are about one-quarter of a mile north-west of Wikhomaw. Besides several small deserted pits, there is a long trench cut in the serpentine, about 100 yards in length, 10 feet in width, and about 25 feet in depth in places. The trend of the cutting is east-west but in places swings between E N E and W S W.
(d) The Namshamaw dyke
The following outcrops of jadeite are situated in the neighbourhood of Namshamaw (25° 45’ 31”, 96° 22’ 28”):
(1) Namshamaw.
(2) Mawsitsit.
(3) Wayutmaw.
This dyke strikes in the same direction as the Pangmaw dyke, with a W N W -E S E trend.
Namshamaw: The jadeite workings of Namshamaw are situated near the confluence of the Namsai and Uru chaung. Blocks of jadeite of irregular shape, which seem to have travelled little, occur in red earth formed by the decay of the serpentine. Very likely the jadeite boulders excavated here represent disintegrated portions of a dyke which has either not been exposed yet or lies a little to the west. Early in 1929, Chinamen were working for jadeite here. A little to the north of Manshamaw lie the deserted workings of Konfimaw, making an occurrence of red jadeite (konpi).
Mawsitsit: The deserted workings of Mawsitsit lie about half a mile west (slightly north) of Namshamaw in a stream and adjoining it. The old pits are lying filled with deep water, thereby concealing the relationships of the rocks. The local people recognise two varieties:
1. Mawsitsit (chromo-jadeite) of dark green colour.
2. Kyet tayoe (chrome garnet) bright green colour.
Of the two, Mawsitsit finds most favour as a semi-precious stone.
Wayutmaw: The jadeite outcrop of Wayutmaw is about a mile west-northwest of Mawsitsit. At the top, there is an overburden about 6 feet in thickness which overlies the weathered jadeite, and the mines did not go much deeper than that. Several old pits are still to be seen. Fairly big boulders of chromite were observed near this locality,
2.Detrital Boulder Workings.
Two localities in the neighbourhood of Tawmaw were worked for detrital jadeite boulders in the past: (1) Pan Din Maw (25° 41’17”, 96° 16’23”), (2) Paim-ma-chait (25° 38’51”, 96° 15’). These very shallow or almost surface workings deserve separate treatment since they constitute a class by themselves.
(1) Pan Din Maw: The jadeite-bearing locality of Pan Din Maw was discovered by a Kachin about 20 years ago. It was worked for only one year about six years ago, but as a valuable mineral was not found in any quantity, the pits were deserted. The latter can be approached by a woodcutter’s path, bifurcating from the main Tawmaw-Lonkin road, a little over a furlong E.S.E. of mile 41, marked on the map (92 C/6). A number of very shallow pits are to be seen on the left bank of a small unnamed stream, flowing W N W-E S E, which are a little over a mile E N E of the spot where the path leaves the main road. The pits are only 2 to 3 feet deep, and no jadeite occurs at a depth of 4 feet. It is found in the form of partially worn boulders along with serpentine. It is very likely that these boulders were detached from the dyke exposed at Tawmaw and transported for some distance before being embedded in the red earth of their present home.
(2) Paim-ma-chait: The second locality is situated about 2 ½ miles S W of Tawmaw, and lies one-third of a mile northwest of the Tawmaw-Lamong road. About 30 years ago, Kachin hunters discovered the place. Some 20 years ago, it was the scene of mining activity for one year, but it was ultimately abandoned for the same reason as Pan Din Maw. Between 40 and 50 old pits are to be seen, and their diameter varies between five and four feet, the maximum in rare cases being five feet. Their depth varies from three to four feet, and in rare cases it is as much as six feet. They are all on the right bank of Paim-ma-chait Chaung, and boulders of jadeite are also found in the bed of the stream itself. Jadeite, as in the previous case, is found in the form of boulders, and to test the quality of the stone, they were broken with hammers; very ig ones were cracked with fire. Amphibole occurs as inclusions in the jadeite. I was told that only one stone, of the value of Rs180, was found along with several smaller ones valued at about Rs20 each. A number of chromite boulders were discovered scattered in the stream.
3.Jadeite workings in the Tertiary Conglomerates.
A. In the neighbourhood of Kansi (25° 47’ 1”, 96° 22’48”), the following workings occur: (1) Pangmamaw, (2)Mutantumaw, (3) Samhtanmaw, (4) Shilamaw, (5) Sanimaw, (6) Aungbilemaw, Hpelaimaw.
All these workings, except the last, which was not visited by the author, lie in the Tertiary conglomerates, and the torrential streams descending from the neighbouring hills of serpentine with jadeite must have been responsible for their deposition.
(1) Pangmamaw: The old workings of Pangmamaw are to be seen in the Pangma hka and its tributaries. Kachin worked the banks of the stream and sometimes the adjoining ground for boulders of jadeite in the past. The workings are situated in the Tertiaries, which comprise soft, bluish, greenish, and yellowish sandstones, shales, coarse grits, and conglomerates. The list includes both coarse and fine varieties, and quartz, quartzite, schists, serpentine, and chromite take part in their constitution. Some of the boulders of serpentine are huge and must have been derived from the hills on the east, where the Pangma Chaung takes its source, but the Tertiaries must have been in position before the establishment of the present drainage system.
(2) Mutantumaw: One of the main tributaries of the Pangma chaung is called the Mutantu hka, and hence the name of the workings. These workings have been deserted, though formerly Kachins, Shans, and Chinese worked here. It is reported that the quality of the jade is not good and is rather scarce.
(3) Samhtanmaw: The workings of Samhtanmaw lie in a small tributary stream (of the same name) of the Pangma hka, which joins the Uru River near Kansi.
(4) Sanimaw: The workings of Sanimaw are situated in the Sani hka, east of Kansi. The overburden, about 6 feet in thickness, is underlain by the boulder bed, about 4 feet in thickness, consisting mostly of partially worn boulders of serpentine and crystalline schists. The boulders of jadeite itself are angular and irregular in shape, showing that they have not undergone much transport. Several ore pits are to be seen in the neighbourhood of the stream.
(5) Shilamaw: The workings of Shilamaw lie in the stream of this name, which joins the Uru River below Kansi.
(6) Aungbilemaw: The old jadeite workings known as Aungbilemaw lies in the lower course of the Seintu hka. (to be continued).
References: Chhibber, H L, 1934: The Mineral Resources of Burma, Macmillan and Co Limited, St Martin’s Street, London.
