Waste

  Bricks

  Coal Products Chart

The wide variety of residuals resulting from destructive distillation of coal, including the processes resulting in manufacture of artificial gas. The chart was produced in 1923 by coal-combustion expert Alexander Lowy and appeared in several editions of Rogers' Industrial Chemistry, edited in later revisions, by C.C. Furnas, here as Table 7, from the Sixth edition (1942)  (click on the image for a larger version of this scanned chart).

  Coal-Gas Tar-Residual Sources

The coal gas process in the post-1900 period, yet not much departed from that of the 19th century. The diagram has been modified from that produced by Professor Jerome J. Morgan (Columbia University, from about 1922 to the 1950s, and prominent consulting manufactured gas engineer). Modification deal with a color code in which gas is stored, mixed or sold, green denotes particular steps in the manufacture, clarification and purification process, and red signifies the most likely places for generation and leakage or spillage and at which today's site and waste characterizes should expect to encounter relative large caches of on-site coal tar residuals. At the same time, but not shown, we must remember to search for one-site and offsite dumps of liquids and solids, as well as for such dump sites within about a half mile of the plant, generally as unengineered dump fills in formerly topographically low areas. Typical locations of leaks are shown by the wiggled line and those typical points of waste effluent discharge by straight arrow symbols (Artwork by Robin Snyder, Gas Works Illustrator; rsnyder@aol.com) (click on the image for a larger version of this scanned chart).

  Brass Holds up Well

Yet unidentified bronze retention bolt head, probably from a smaller unit of the gas clarification sequence, possibly from a tar separator unit. Patented in 1889 and manufactured at Philadelphia. Typical high degree of preservation of non-metallic gas works wastes preserved in tar-contaminated soil (Photograph by the author).

  Fragment of Broken Coal-Gas Retort

Portion of the lower left curve of a ceramic gas retort for manufacturing coal gas, and of the Dee shape commonly used to avoid corner stressing in heating cycles. A typical closed-end, Dee-shaped, pre-formed, single-piece clay retort lasted from a few months to in excess of two years. Much of the dumped and now buried gas works solid wastes were bench bricks and broken retorts or checkerbricks from water gas, carburetted water gas or oil-gas shells (Photograph by the author).

  Gas Piping

Significant advances in forming gas pipes occurred in the 1870s, during which time seamless pipes were developed. This photo shows the older-style seamed gas pipe, generally used at the plants up until the 1870s, following the manner in which gun barrels had been made for two hundred years previously.

  Pipes Bearing Gas Tar

Gas pipes often are found exuding tars, at gas-plant dump sites.

  Junked Unserviceable Gas Meter

Intact early 1890s model American Gas Meter Company (Philadelphia, PA) residential gas meter. Likely discarded when the meter shop could no-longer effect a repair to the meter. Its largely tin body was well preserved by coal-tar soil-contaminants at the dump site (Photograph by the author).

  Brass Gas-Meter Labels

Gas meters commonly bear fine embossed thin brass labels, brazed onto the meter housing. These labels, from Philadelphia, bear unique serial numbers, as the means of control over meter accuracy in measuring the consumer's gas draw (Photograph by the author).

  Bottles are Useful in Age Determination

Site age determination has been raised to a high art by archaeologists, industrial historians and bottle collectors themselves. Most bottles can be age-estimated to within about five years by astute archeologists and reliance on the numerous regional bottle and glass guidebooks. Age determinations are treated as "minimum" unless other supporting evidence is discovered (Photograph by the author).

  Fouled Wood-Shavings as "Box" Wastes

Manufactured gas wood-shaving, spent scrubber or purifier medium. Cellulose such as this was the prime means for trapping cyanides at coal-gas plants, the cyanide (CN) forming from two natural ingredients of the feedstock coal, carbon (C) and nitrogen (N). Geologists, engineers and technicians who log and sample field explorations must take care to allow (or return) to allow the diagnostic Prussian-Blue wood shaving color to bloom in the new oxidizing environment after having been liberated from the soil mass of gas-plant dump sites. Normally, cyanides form around coal-gas plants, but particular conditions at Pacific Coast Oil-Gas plants are known and observed to support the formation of cyanide and generally, when present, will bloom a slight Prussian Blue sheen after being exposed to ambient air (Photograph by the author).

  Broken Coke Fork

Remains of a standard gas-plant coke fork, showing rust damage from a hundred years of burial at the gas-plant dump (Photograph by the author).

  Purifier Box Spent Lime

Many management options were tried, including pawning the waste off on truck farmers, who usually found that the acidity of treated soil increased rather than being buffered. In other places, small rows of spent box-waste lime was used to border gardens as a barrier to crawling vegetation-consuming insects. All-in-all, spent lime generally was dumped on or around the gas works

  Spent Lime

Often known as "Blue Billy", spent lime became fouled with sulfur and, sometimes, cyanogens, imparting the noted color.

  Lampblack

Chemically, lampblack was nearly pure carbon and was considered basically valuable in the industrial east, where it served in the manufacture of vehicle tires, bowling balls, inks, and phonograph records, to cite a few beneficial uses. However, in manufacture of Pacific Coast oil gas, the lampblack exceeded all manner of manufacturing use, and commonly was fouled by absorbing toxic PAHs in the course of its separation from the gas and commonly was dumped. At Portland, Oregon, the U.S. Army District Engineer cited (1906) the gas company with a violation of the Refuse Act of the 1899 Rivers & Harbors Act and put an end to discharge into the Wilamette River. As a result, the Portland Gas Light & Coke Company devised a method of separating, drying and briquetting the waste into commercial fuel, a technology taken up at Los Angeles, but apparently not at San Francisco.

  Cyanogens and Lampblack

Theoretically, cyanogens should not form in the process of oil-gas manufacture, but the opposite was the case with the firms eventually consolidated into what today is the Pacific Gas & Electric Company, whose Chief Engineer, the highly-respected Edward Campbell Jones, discovered what is seen here and proclaimed such in print, about 1912. The cyanogens exhibit their blues generally only upon exposure to air, which is a lesson that must be learned in site exploration, that Pussian Blue seldom forms and is observed in drill cuttings until hours or days after their exposure to the atmosphere.

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