The Calamine Mines of Tuyên-Quang, Echo of Mines and Metallurgy 1918

This calamine mine is located behind the Trang-Da mine, in the upper valley of the Crocodile torrent. Exploited first at the summit, at an altitude of 400 m., with a transporter cable descending to Trang-Da, the vein is now exploited further down.
Six floors of galleries, not to mention open-air quarries, open up at various altitudes, between 180 and 300 meters; It was impossible to think of bringing the ore up to the summit which divides the valleys of the Crocodile and Trang-Da, in order to take advantage of the transporter cable. Commander Cadars was therefore led to evacuate the ore through the Crocodile valley which flows downstream from Fort Giovanelli.

For this, he builds a small narrow-gauge railway with a track width of 0.60 m and a length of 6 km. This railway starts from a point at an altitude of 180 m, where carrier cables bring the ore from the various levels (the loaded cart descends by its own weight and that of the ore, raising the empty cart upwards: no mechanism is needed). The extremely picturesque route then follows the stream, through the forest, sometimes along the hillside, sometimes clinging to the rock above a precipice, sometimes crossing a bridge or some deep ravine.

At km 5.300, it reaches a platform at the level of the mouths of two furnaces whose construction has just been completed. At the base of the furnaces is a large warehouse capable of holding on its cement platforms more than ?.000 tons of roasted ore and huge stockpiles of bags; from there, the railway continues to a dock on the Claire River (downstream from the School of Agriculture), 700 m from the warehouse.

The track is built with 9 kg rails from the Fai Foo (Annam) railway; it was inaugurated just fifteen days ago. Of course, given the impossibility of obtaining rolling stock in Europe (due to the First World War), a rougher version had to be improvised, where the tilting metal wagons are replaced by huge wooden boxes with a double-sloped bottom. It is not attractive, but it serves its purpose; there is no locomotive, and since the track descends with a constant slope, a small effort from a pushing coolie is enough to overcome the resistance of the curves; for the ascent, the equipment is pushed by hand until oxen are available.

What strikes a visitor most at Yên-Linh is that such a vast mining operation employs no mechanical power: brought by wheelbarrows or small carts from the depths of the galleries, the ore, upon being brought to the surface, is sorted into large and small pieces by women on a platform set up in some hollow, and from there, it slides along cables toward the railway head. Later, a washing plant will be built; meanwhile, in the six years that the mine has been in operation, only the ore in pieces has been sold, accumulating in gigantic heaps the fine ore mixed with earth that requires washing. There are over 150,000 tons of ore there that will cost nothing to extract once the washing plant is installed; in addition, there are stocks of ore chunks accumulated on all the platforms awaiting the resumption of export, valued at more than 600,000 francs.

The Yên-Linh ore is very rich and generally reaches 5%. It is sad to see this accumulation, which in France would be worth 1 million, and which must remain there, on the mine floor, due to lack of transport. And this is the case for all the mines. The nature of the ground at Yên-Linh requires, in the tunnels, tremendous timbering, and the question of wood becomes difficult.
It seems paradoxical when you see these immense forests. But these are virgin forests, that is, poor in useful wood and very difficult to exploit. There are indeed the famous reserves of the Forest Administration, but everyone knows what they are: scrubland or virgin forest without value, where all that has been done is to surround them with posts with a sign: reserves, but industry does not have eternity in front of it to wait and see what the Administration is incapable of ever doing: practical eucalyptus.

The Yên-Linh mine has vast areas that it will clear to plant the type of wood recognized as both the most suitable for mine timbers and the fastest-growing, and in six or seven years, it will thus easily have all the wood it needs.