Around the Mill
"Large blocks were marked before removal from the pit, to indicate whether they were to be thrown away, or used for millstock, roofing, or blackboards. Those to be used were loaded on four-wheeled truck trams and pushed by hand or hauled by mules."
Source: From Rock to Roof
Once the slate had been separated from the walls of the quarry, the first process was to raise the material out of the pit. In all of the Pennsylvania slate districts the quarries were equipped with steel or wooden masts, which supported steel cables that were thrown across the mouth of the opening and then anchored by heavy guy-ropes on the side opposite the landing. This system, which was unique to this district was known as the incline cableway.
Once out of the pit the slate still needed to be moved around the yard for cutting and splitting purposes. Most of the material, once out of the pit, was still weighed by the ton, requiring a system that could move extremely heavy loads. It is easy to understand why the railroads ultimately became so important for slate transportation to other cities. It was not difficult to make the connection between the value of hand pushed rail carts and full scale railroads.
Moving the Loads
Four methods of handling raw and finished slate in and around the mill were commonly utilized. These were, by boom, hand car, horse-power, and crane.
Although similar systems were common, each mill would often determine what worked best for them. Many slate mills were equipped with a block and tackle attached to a rotating boom or "derrick". Such an appliance was used outside the mill shed for moving blocks from quarry trucks to the saw tables, or within the building to shift pieces from one machine to another, the length of the horizontal arm of the boom having been the measure of its working radius. In some mills the block and tackle could be moved along the length of a horizontal arm. In one mill a chain and grapple were mounted on an S-shaped track, being used for moving slate from saw table to planer. In some mills, overhead cranes, traveling on tracks attached to the roof, were installed. Five-ton Shepard cranes were favored for the equipment. The initial expense could be a deterrent, but the crane certainly expedited the handling of waste and of larger blocks and so probably payed for itself very quickly.
Much transportation was effected by hand-pushed or horse-drawn cars, moving on a track which was laid along the middle aisle of the mill but also extended outside the mill to allow for transporting slate from the incline cableways.
Yard Transportation
Blocks hoisted from the quarry pit were usually placed on small 4-wheel cars known as quarry trucks. Movement was done by hand or horse where the tracks were nearly level, or by a cableway on hills, allowing slate to be moved to splitting sheds or mills for subsequent treatment. The characteristics of the stone itself led to the development of these small open cars that carried the slate in its various forms. These were first developed on the narrow gauge railways serving the slate industry of North Wales in the late 18th century. They were initially used on horse-drawn tramways, but survived with only minor modifications into the days of locomotives. Some of the mills for finishing the slate were in towns, and the quarries may have been several miles away, which meant that the rough blocks needed to be transported by teams and wagons or by trucks.
"Transportation also involves the conveyance of the finished product to railway sidings or storage yards. As roofing slates are commonly split at shanties situated on high waste heaps, the slates are conveyored down to the normal ground level by cable cars. Long 8-wheel cars are commonly used. In many places where transportation lines are not immediately available the slates are hauled by teams and wagons or by motor trucks for distances of a few hundred yards to several miles."
Bowles, Oliver. 1922. The Technology of Slate, by Oliver Bowles. U.S. Government Printing Office.
A 2014 view of the steel derricks and hoist houses behind, which still stand at the abandoned American Bangor Quarry.
To see a 3-D interactive representation of the incline cableway system CLICK HERE.
An image of a quarry truck from the 1912 trade catalog from the S. Floury Manufacturing Company which was located in Bangor.
Image Credit: Bowles, Oliver. 1922. The Technology of Slate, by Oliver Bowles. U.S. Government Printing Office, p.90
The map above shows the significant value that railed systems offered to the industry. Within this mill yard single line tracks showed the paths of closed rail systems used on site and most likely dedicated to quarry trucks, while the double line tracks represented the rail lines associated with commercial rail lines that would transport product to market.
Image Credit: Pennsylvania Geological Survey
In the yards near the mill buildings booms would be used to load and unload the material.
Waste
With an industry that suffered more than 60 percent waste, an important part of yard transportation was involved in the disposal of waste rock. Tracks from the edge of the quarry would be used to clear out waste removed directly from the pit These tracks of moderate to steep incline usually lead over the waste heap which gradually increased in height and in lateral extent. A hoist engine with a cable and drum was often the mode of power, many of these systems being built by Flory Manufacturing.
Waste from the splitting shanties and from the mill also had to be conveyed to a dump. Solid blocks of inferior rock, in the range of 1 to 4 tons in weight were hoisted by chain and deposited directly on cars for transportation to the dump. Four wheel side-dump cars were most commonly used for these larger blocks while smaller sized waste fragments were placed in metal pans about 5 or 6 feet square and having three sides each 1-1/2 to 2 feet high. The pan, having one side open, was then placed on a side-dump car with the open side toward the direction in which the car top tilted. The pan was held with an iron hook to prevent it sliding from the car when its contents were dumped. The dumping of waste was often fairly continuous so one or more men would be constantly employed at the upper end of the incline to dump cars and extend the track.
Quarry trucks could easily be linked together to create a train which could then be hauled to the mill building.
Unique to Bangor Union Quarry was their means of transporting slate to the trains for shipping. Located about two miles from the railroad, slates were transported by overhead tramway from where they were made, to the warehouse which had independent switches for the railroad. The buckets on the tramway could each hold about 1/3 of a square of roofing shingles, which could be loaded quickly and without too much concern for damage resulting from poor quality roads. Once the slates arrived at the terminal, the buckets would then return to the quarry full of coal needed to fire the boiler.1.