ONTARIO DIVISION. 
361 
There is now a back* with an average depth of perhaps one hundred and fifty feet on the 
slope of the vein, ready for removal by the miner, and ready drained ; so that if large bodies 
of ore exist there, they can now be removed without additional expense, except that merely 
of mining, since all the necessary preliminary expenses have already been incurred. 
The advantages of these mines are, 
1. Contiguity to water transportation, and nearness of market. 
2. Great depth to which they may be drained without machinery. 
3. Abundance and cheapness of fuel for smelting. 
The disadvantages are, 
1. Uncertainty of the quantity of ore. 
2. The more or less intimate mixture of the galena and blende. 
3. The siliceous nature of the gangue. 
The explorations in progress will demonstrate the probability or improbability of the mines 
being prospectively productive. 
The mixture of the galena and blende offers a practical difficulty in the smelting operation, 
and various methods have been tried to effect a separation, so as to be enabled to smelt the 
ore and obtain the lead ; but they had not proved successful up to 1840. At the time of my 
visit, they were erecting shaking washing tables, which (the ore being first crushed or 
stamped, and then separated into uniform sizes by screens of different degrees of fineness,) 
has proved successful, and the ore can now be smelted. 
The process for separating the blende or zinc ore also separates the greatest portion of the 
siliceous matter, so that the future value of the mines will depend only on the quantity of 
ore, and the expense of the separation. 
There is a strong probability that there are valuable deposits of lead ore in the Shawangunk 
mountain, since so much lead ore has been taken from this and other mines, and from its 
having been found in so many places. 
The zinc ore in the Shawangunk mine, as far as it has been worked, is believed to have 
exceeded the lead ore in quantity. At the time of my visit, they were taking out large quan¬ 
tities of both these ores. 
It is thought probable that the ores may prove more abundant, and richer in lead, when 
the workings shall have reached the slate rocks that underlie the grit; but as the vein does not 
dip at a much greater angle than the strata, it is not probable that these rocks would be 
reached in this mine, without penetrating to at least the level of thb valley, or five hundred 
to seven hundred feet below the present workings. 
The lead ore of this mine contains some silver, but I have not ascertained the proportion. 
I cupelled a few grains of the lead obtained from some of the ore. A small but distinct 
globule of silver remained. Prof. Beck, of the mineralogical and chemical department of 
* The “ back,” in mining phraseology, means the mass of a vein that has not lieen removed, and lying above the galleries 
that have been opened. 
Geol. 1st Dist. 
46 
