The purer the water the better it will be for amalgamating purposes, and in cold climates it is desirable to make provision for heating the water supplied to the battery.  This can be done by means of steam from the boiler led through the feed tanks; but where the boiler power is not more than required, waste steam from the engine may be employed, but care must be taken that no greasy matter comes in contact with the plates.  The exhaust steam from the engine may be utilised by carrying it through tubes fitted in an ordinary 400 gallon tank.

Reducing appliances have often to be placed in districts where the water supply is insufficient for the battery.  When this is so every available means must be adopted for saving the precious liquid, such as condensing the exhaust steam from the engine.  This may be done by conducting it through a considerable length of ordinary zinc piping, such as is used for carrying the water from house roofs.  Also tailings pits should be made, in which the tailings and slimes are allowed to settle, and the cleared water is pumped back to be again used.  These pits should, where practicable, be cemented.  It is usual, also, to have one or two tailings dams at different levels; the tailings are run into the upper dam, and are allowed to settle; the slimes overflow from it into the lower dam, and are there deposited, while the cleared water is pumped back to the battery.  Arrangements are made by which all these reservoirs can be sluiced out when they are filled with accumulated tailings.  It is well not to leave the sluicing for too long a period, as when the slimes and tailings are set hard they are difficult to remove.

Where a permanent reducing plant is to be erected, whatever form of mill may be adopted, it is better for many reasons to use automatic ore feeders.  Of these the best two I have met are the “Tulloch” and “Challenge” either of which can be adapted to any mill and both do good work.

By their use the reducing capacity of the mill is increased, and the feeding being regular the wear and tear is decreased, while by the regulated feeding of the “pulp” in the battery box or mortar can be maintained at any degree of consistency which may be found desirable, and thus the process of amalgamation will be greatly facilitated.  The only objection which can be urged against the automatic feeder is that the steel points of picks, gads, drills, and other tools may be allowed to pass into the mortar or mill, and thus cause considerable wear and tear.  This, I think, can be avoided by the adoption of the magnet device, described in “Rules of Thumb.”

There are many mines where 3 to 4 dwt. of gold cover all the cost, the excess being clear profit.  In fact there are mines which with a yield of 1 1/2 to 2 dwt. a ton, and crushing with water power, have actually yielded large profits.  On the other hand, mines which have given extraordinary trial crushings have not paid working expenses.  Everything depends on favourable local conditions and proper management.