124 Records of the Geological Survey of India. [vol. vir. 
Limestone. —Besides kunkur there is some impure rock-limestone near the village of 
Paharpur at the base of Panchet Hill. It is a well known bed, and is marked on the revised 
map of the Raniganj field. It contains 56'43 per cent, of carbonate of lime, and varies in 
thickness from 12 to 15 feet. A large quantity of stone might be obtained from it, but it 
possesses the. disadvantage of dipping at a high angle. 
Calcareous nodules. —There is, in addition to kunkur and rock-limestone, another sourco 
of flux, and that is the calcareous nodules in the clay beds of the Panchet series. The 
average proportion of carbonate of lime was found to be 66’8 per cent. The importance of 
this supply is quite subordinate to the kunkur, but it is well to hear it in mind. 
Calcareous concretions also occur in the Talohir series. 
Limestone beyond the field. —In reference to limestone beyond the field, I have no 
additional information to record regarding the stone discovered by my colleague Mr. Mallet; 
hut I have had an opportunity of inspecting a small quantity of limestone brought from 
the south side of the Damuda near Raniganj. It looks extremely pure, and if it occurs in 
anything like quantity, it would be of great value.* I scarcely anticipate, however, that it 
will be found in abundance, and the kunkur will, in the event of any attempt to establish 
large iron works, probably be the flux on which to rely. 
Use of kunkur in Birbhhm iron works, 1860.—Kunkur was successfully employed in 
the Birbhum iron works, and Mr. Blanford, when reporting upon them in 1860, records as a 
fact that Mr- Casperz, the manager, found it advantageous to partially burn the kunkur and 
then to slake it, in order to separate the more impure external parts. 
This process could only he advantageously applied to the more regularly concretionary 
varieties of kunkur, showing centrical concentration, for the ordinary form of this rock is 
without any distinctive purer core. 
Relative quantity of ore and kunkur. —I stated in my former paper that equal quanti¬ 
ties of ore and kunkur would he required for the production of iron in a blast furnace. 
In the Birbhum works, a less proportion of kunkur was found to be sufficient, only 3 of 
kunkur to 7 of ore being necessary. Charcoal, however, was the fuel then employed, whereas 
in my experiments, coke containing as much as 30 and 40 per cent, of ash was used, and 
the ore was not quite so clean. With better coke, and an ore with an average of 42 per 
cent, of iron, the amount of kunkur requisite would be less. In estimates of the cost of 
manufacture, however, it is as well to he on the safe side, and equal quantities ought to bo 
allowed for. 
Malleable iron. —For the production of malleable iron, the direct process, which, I am 
indirectly informed, has been quite recently perfected by Dr. Siemens, greatly improves the 
prospect of the undertaking in India, for the impure as well as for the purer ores. One of 
the chief objections made to this process by iron-masters in England, that a greater propor¬ 
tion of the iron passes into the slag than occurs in the present method of manufacture, 
does not apply to the case in India, where a saving of materials is quite a secondary consi¬ 
deration to that of a saving in skilled labour. 
The advantage claimed for this process, of not bringing the phosphorus into combina¬ 
tion with the iron, removes one of the most serious impediments to the development of the 
great advantages for iron manufacture otherwise possessed by the Raniganj coal-field. 
* Since writing the above, I have visited the locality whence the limestone was taken. It occurs as nearly pure 
calc-spar in small veins, striking N. and S., through a decomposed bed of gneiss. It will pay lor extraction for 
special purposes, but cannot be looked to as a source of flux. 
