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| Slate and Phyllite |
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Commercially, the slates are defined as layered stone that can be split into slices of thickness ranging from 8 to 14 mm. Slates/Scihists are generally fine grained and occur in various shades of grey to steel grey, greenish grey, dark grey, purplish grey, brownish, ash and sometimes with other pleasing colours. Slates/Schists have varying degree of hardness. The harder ones are being sometimes used for flooring.
These are low cost decorative stones having wide applications after cutting for use in interior as well as exterior decorations.
Schist and slate stones are argillaceous rocks having different grades of metamorphism. Certain planes of easy split called 'schistosity', are developed in these rocks due to metamorphism, which make these rocks suitable for decorative use. The slates/schists having good and even cleavages are valued much. The planes of cleavage are related solely to the direction of pressure to which the material was subjected and not to the bedding plane. |
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Micaceous and chlorite slates/schists are generally of good quality.
These are used for roofing, paving, shelves and flooring purposes in the rural areas in and around the places where it is mined. Now a days slates/schists are cut in to tiles and used for wall claddings. Slates are also used for making school slates |
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| Geographical Distribution |
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Slates, schist and phyllites of dimensional use are found associated with Delhi and Aravalli Supergroup of rocks in parts of Ajmer, Alwar, Jaipur, Sawai Madhopur, Bharatpur, Bundi, Pali, Tonk, Udaipur and Chittaurgarh districts. Slate deposits of Alwar are conspicuous both in regard to quality and quantity.
Besides, Bar conglomerate in Pali district and calc-schists in Ajmer district, mica schist in Bhilwara district etc. are quarried for use as roofing and flooring slabs.
Districtwise distribution of Slates, schist and phyllites is shown below:
Ajmer: Sheopura, Lulawa, Nai Khurd (Beawar).
Alwar: Basai, Kayasa, Kund (Behrod).
Tonk: Devli, Dhuni, Anwa, Uncha.
Pali: Bar.
Bhilwara: Badnor, Tikar.
Dungarpur: Balwara.
Chittaurgarh: Gosunda.
Udaipur: Godan, Gogunda. |
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| Future Prospects |
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Slates have potential export market. The multi coloured slates of Kund, Behror, tehsil & distt. Alwar have export demand for a long time. It is used for roofing, tiling, for wall paneling, wall-cladding etc. Copper-red, green, grey, silver-grey coloured slates of Badnor and Tikar (Bhilwara) and Dhuni, Anwa (Tonk) are forming export market. Pali, Dungarpur and Bundi districts are also emerging as slate producer districts. Chief importers are Australia, Netherland and Switzerland. Export can further be increased with the application of better mining and processing techniques. |
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ASTM/
Indian Standard
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C-121 |
C-120 |
C-217 |
IS 1237 Guidelines |
Area
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Avg. Wear mm |
Mxm. Wear mm |
| Panther Jhalawar |
2.0 |
2.9 |
0.04 |
1.7 |
1.9 |
| Deoli Tonk |
2.4 |
1.9 |
0.06 |
5.7 |
5.9 |
| Copper Tonks |
1.2 |
14 |
0.09 |
11.7 |
11.7 |
| Silver Grey Bhilwara |
0.3 |
46 |
0.05 |
26 |
2.8 |
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Year |
No. of
Lease |
Production
(thousand
tonnes)
|
Sale
Value
(thousand
rupees)
|
Revenue
(thousand
rupees) |
1997-
1998 |
32 |
8.140 |
2923.60 |
550.990 |
1998-
1999 |
42 |
6.56 |
4054.00 |
1126.935 |
1999-
2000 |
44 |
12.019 |
105.450 |
1383.360 |
2000-
2001 |
43 |
7.775 |
36.730 |
1147.220 |
2001-
2002 |
37 |
8.937 |
16.350 |
968.470 |
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District |
No. of
Lease |
Production
(thousand
tonnes) |
Revenue
(thousand
rupees) |
| Alwar |
23 |
5.034 |
740.00 |
| Bharatpur |
3 |
0.056 |
57.36 |
| Bhilwara |
2 |
- |
35.03 |
| Bundi |
5 |
03.951 |
110.29 |
| Dausa |
1 |
0.028 |
25.79 |
| Toak |
3 |
0.0670 |
0.00 |
| Total |
37 |
8.939 |
968.47 |
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