In the spring of 1913, inventor Arthur Langerfeld unveiled his automatic coal and slate separator at the Spencer Coal Company’s coal breaker in Dunmore, Pennsylvania.
This new machine promised efficiency, while also having the moral upside of making the work of “breaker boys” obsolete in the processing of anthracite coal. Activist photographer Lewis W. Hine took his picture with the machine inside the Spencer breaker on March 18, 1913.
Langerfeld emigrated to the United States from Germany in 1868 and made his home in Lackawanna County where he worked in the mines around Scranton. By the 1910s, he was working on invented this machine to automatically sort coal from slate in the processing of anthracite.
In June 1913, he published an article in The Colliery Engineer, a mining industry publication, about his new machine, how it functioned, and the efficiency it brought to the anthracite industry.
New Mining Machinery
Langerfeld Coal and Slate Separator
By Arthur Langerfeld
The cleaning of the coal in the Spencer breaker, in Dunmore, was recently changed from hand picking to mechanical separation, and all the stove, chestnut, and pea coals are now cleaned entirely by Langerfeld separators.
There is only a small quantity of egg coal made at this colliery and therefore no machine for this size was installed. There are two sets of these separators. Each set consists of three machines; one stove coal separator of 200 tons capacity, one chestnut separator of 200 tons capacity, and one pea coal separator of 100 tons capacity.
The capacity of each set being 500 tons, the intake capacity in 9 hours of steady running while feeding to full capacity is about 1,000 tons. The output of clean coal would therefore be 1,000 tons, less the refuse deducted from the intake capacity, besides the allowance made for the time during which no coal comes into the breaker and for the time during which coal does not come to the full capacity of the machines. The actual output of clean coal depends therefore on the quality of the coal fed in, and on the time during which the machines are fed to full capacity.
The economy that has been effected by the installation of these separators was not only the wages of the boys who were employed to pick slate by hand, but also a saving of the salable bone and coal that was formerly sent to the dump with the slate.
This double saving is brought about because these machines are adjustable and they make a four-part separation; viz., coal clean enough to pass inspection; bone with little coal of the size and very little slate, suitable for reducing to one size smaller; slate or bad bone with hardly any coal of the size and with very little rock, suitable for reducing two sizes smaller; and rock with only about 1 per cent. of coal of the size and only 2 or 3 per cent. of salable bone.
The separation of valuable bony coal is an economy, because it increases the car average or quantity of salable coal obtained per mine car dumped in the breaker. This economy is brought about by running separated bony coal to rolls set to reduce it to the next smaller size, and then running this broken bone back in the screens together with the run of mine.
This increases the quantity of material going to the separators and reduces the quantity going to the refuse dump. Ordinarily this process would make the cleaning of the coal too difficult because the quantity to be cleaned is not only increased, but it is also made dirtier, and especially high in bone. Bone is far more difficult to separate from coal than slate, and coal is condemned for too much bone as well as for too much slate. The standard specifications provide that stove coal must not contain over 3 per cent. of bone if there is 4 percent. of slate in it, and it is customary to allow 2 per cent. more of bone for each 1 per cent. of slate.
If there is in it less than the 4 per cent. allowed; therefore, in case there is no slate at all, there could be 11 per cent. of bone. The standard limitation for chestnut is 5 per cent. slate and 5 per cent. bone; and it is similarly customary to allow 2 per cent. bone for every 1 per cent. slate below 5 per cent., so that in chestnut containing no slate there could be 15 per cent. bone. For pea coal there is no provision for the bone allowed, and allowance of slate is 10 per cent. It is customary to also allow about 10 per cent. bone in this size so that in case there is no slate in the car of pea coal, it would be allowable to contain 30 per cent. bone. In practice there is seldom less than 5 per cent. slate in pea coal, so that 20 per cent. bone is the limit in this case.
Much of the anthracite now sold is paid for on the heat unit basis; that is, the number of British thermal units it contains.
It is said that some bone actually gives more heat than some coal. The peculiar construction of the Langerfeld separators classifies this kind of bone as coal, by reason not only of the gravity of the pieces fed in but also by the difference in frictional resistance, which has been found to be almost exactly in proportion to the percentage of carbon in the coal or bone. This classifies the pieces at their heat-giving value rather than by their appearance or gravity, and makes this kind of separation economical both for the coal company and for the public.
These separators contain seven different parts, and as each part has a definite function it can be adjusted to do its work without materially interfering with any of the other parts. The first part separates the material into two streams, one containing the largest and thickest pieces, the other containing the smallest and thinnest pieces, thus the first step in the process is not a separation by quality but by thickness. This first step or classification differentiates in quality, because most slate is thin or flat and most of the coal is thick or lump shaped; but there are some seams from which the coal splits as thin as slate, and for this reason a separation depending only on the difference in thickness is unreliable and not economical.
The next two parts in the separator feed the two streams of material piece by piece, into frictional differentiators. The feeders are the most novel feature in the separator, as they feed each piece separately, spaced apart both lengthwise of the machine and crosswise, so that no collision takes place between pieces as they slide down on the differentiating slides. In all other separators or pickers the coal is fed either in dashes or in a continuous stream, so that the pieces collide and interfere with each other in their separation and spoil results to that extent.
The first separation is made in two parts of the machine. In one all the lump-shaped pieces of coal are taken out, and in the other the best pieces of flat coal. What is left in the separator after this first separation is one lot of lump-shaped rough coal, bone, and rock, and one lot of small or flat pieces of rough coal, bone, and slate. Each one of the two classes is then fed into the system of differentiators, consisting of two reverse slides and an intermediate invertor so arranged that each piece slides first on one of its sides and then on its opposite side.
In this way each piece acquires a velocity in proportion to the average quality of two of its sides and therefore is separated with twice the accuracy that can be attained in any of the other ways used in pickers or separators. This makes it possible to make a good bone separation, and in this part of the machine both rough coal and most of the bone are separated.
What is left is a mixture of some lump-shaped rough coal, some bone, and nearly all of the rock, in one part, and some small or flat rough coal, some bone, and nearly all of the slate in the other part. In the next two parts of the separator each one of these classes is again fed to differentiators and only the worthless rock and slate are taken out. The remainder of the materials may be classed as bone, or they can be fed back into the separator for a still better distribution. The quantity of this bony mixture is so small a part of the entire material that, if re-fed, it does not materially reduce the intake capacity.
It has been suggested that such refeeding would cause accumulation, but in practice this is true only to a small and limited extent, because from it a piece goes through the separator a second time and the chances are that it will come out in one of the eight discharges. In this way hardly any of the salable stove coal bone is lost, but goes to the rolls to make chestnut. Nor does any considerable quantity of chestnut size bone go to the dump, because it goes to the rolls to make pea; but pea size bone may be burned at the colliery or go to the buckwheat rolls, and finally go to the pockets for a smaller size.
Results have proven that these separators pay for themselves in a short time. Nor is their cost any greater than first cost of as many separators, pickers, or jigs, as would be required to handle the same quantities, and give anywhere near the same results.
Another economy was effected in this breaker by saving the expense of loading and hauling slate or refuse, there being no slate pockets. The six separators are set in line and a conveyer runs under them the full length of the breaker. All of the separated refuse drops into this conveyer and is taken out by it to an elevator. From the head of this elevator the refuse runs down a chute to the dump.
The only attention that is given to the separators is to set them for wet and dry coal and to adjust them so that the coal will be clean enough.
The cost of cleaning coal by these separators is less than 1 cent per ton for dry coal, including allowance for repairs; but in wet breakers the cost is somewhat higher, because the water adhering to wet coal contains some acid which corrodes the metal parts of the machines.
The room required for these separators is less than was heretofore required for picking chutes for boys, or for as many jigs or other pickers as are needed for the same tonnage.
Langerfeld spent years developing and fine-tuning the machine, but he was still out trying to prove the efficacy and value of his machine through the 1910s.
He also developed schemes to solve mine subsidence in Northeastern Pennsylvania through filling the abandoned mines with ice. Langerfeld ran into problems in 1917 as America entered World War I. The German immigrant took umbrage with how Scranton newspapers were characterizing Germans as blood-thirsty and violent.
Langerfeld wrote numerous letters to the editor of the Scranton Times excoriating them for their anti-German editorials and political cartoons. He received scorn from his neighbors for not being patriotic. Many suggested he should be jailed for his opinions.
We’ll have more on Arthur Langerfeld’s political views, and his support for Eugene V. Debs, in a future post.
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Fascinating, thank you!