The poor fellows in the phosphate business, however, couldn’t get out, and kept digging away, until gradually capital decided it was worth buying the lands after all, and as a result nearly $2,000,000 has been paid for property in the Mt. Pleasant field, about $500,000 in other portions of Maury County, and over $1,000,000 for property in the counties of Decatur, Perry, Lewis, Hickman, Giles, Williamson, Davidson and Sumner. Rock has gradually advanced in price until now 65 per cent blue rock sells at from $2.60 to $2.80 per ton, 75 per cent brown rock at from $3.10 to $3.60 per ton and 78 per cent domestic (4½ I. & A.) at $3.75 to $4.00, while 78 per cent export rock with 3 to 4 per cent I. & A. sells for from $4.00 to $4.25 per ton.
As the prices have increased the cost of production has increased for one reason and another, until now each ton of phosphate rock put on board the cars represents an average cost in labor and salaries of $2.00 per ton. The production for 1904 having been 540,000 tons, the wage earners of Tennessee have profited by this industry to the extent of $1,080,000 during last year alone. On the other hand, fertilizer factories have sprung up all through the interior of the country like magic, and as they now get 75 per cent rock at their factory for less than the freight they used to pay on 62 per cent rock from South Carolina, acid phosphate is cheaper than ever before, and consequently the farmer gets cheaper fertilizer or else better fertilizer for the same money.
The first thing which impresses itself on the mind of almost any visitor to the phosphate fields is the almost universal dependence on hand labor of the simplest pick and shovel kind. This is partially due to the fact that they “just started that way,” and hence the most “experienced laborers” have always done that way; and partially to the fact that after sufficient capital was at hand for the purpose, the varying conditions met with in the deposit made it very difficult to devise appliances suitable for one portion of a mine that would answer the requirements in the closely adjacent portions.
For instance, it is possible in the same open face of a mine to find the overburden varying from two feet to twenty and the rock from a few inches thick, sticking tight to the top of a lime boulder, to fifteen feet in the “dip between two boulders,” while the rock itself will vary from the shaly, partially disintegrated top rock through various sizes to heavy blocks six to eight inches thick and often ten or twelve feet long.
It will therefore be seen how difficult it is to design a machine that will accommodate itself to the handling of this material. The removal of the overburden has been generally accomplished with wheel scrapers. Two companies have used the New Era or Western machine plow with elevator belt loading the dirt into dump bottom wagons alongside. Two steam shovels are now in use, being of the traction type, and occasionally these have been used in digging the rock, though apparently with not sufficient success to justify its continuance. Cableways have never been used to transport the material and this is done largely by wagon and team, though many tram roads with cars propelled either by mules or dinky engines are in use.
The bulk of the rock, however, is dug by the miner with pick and fork, loaded into wagons, hauled out and dumped in windrows on the ground, stirred with a potato plow and harrows, allowed to dry in the sun, taken up again into wagons and hauled either direct to cars for shipping or put under sheds for storage. When an extra good quality of rock is wanted, as for export, a few layers of cordwood are put down and the sun-dried rock put on that. Then, when ready to ship, the wood is fired, and after the rock is cool, it is broken and loaded with forks, when most of the dirt sloughs off, leaving the rock almost perfectly clean.
Some rock can be put from the mines immediately on the wood and burned for export, but generally this will only be a safe domestic rock. Some companies who have water accessible, pick out the large pieces and send them direct to the dry kilns and then the small pieces with the dirt, known as “muck,” are passed through washers, the rock coming out clean, and being deposited on cordwood and burned as above described.
The resulting rock, after being crushed, is passed through screens which separate it in three sizes, from one and one-half inch up going for export, between that and one-fourth inch for domestic, and the dust and one-fourth inch pieces being ground up and sold for direct use or to small factories.
The Century Phosphate Co. has installed a system of dryers and do not wash the rock, but dry it thoroughly in mechanical dryers and then screen and separate it as above.
The reason the larger pieces are as a rule of higher grade than the smaller, is that the dirt and impurity is mostly on the surface of the rock and the greater the proportion of surface to volume the lower the grade in B. P. L. and the higher in iron and alumina.