Brown's Dump
The West Mifflin Mountain Of Slag

Brown's Dump - West Mifflin Slag Mountain
Brown's Dump in West Mifflin. In the foreground is Route 51 and in the distance the County Airport. Before land
development began in the 1960s, this mountain extended farther forward and much further to the right.

Along Route 51 in West Mifflin, just a short drive from Brookline, is one of Pittsburgh's many monuments to its steel-making heritage. It is a large man-made mountain of slag called Brown's Dump.

For over fifty years, Union Railroad slag trains from the Pittsburgh steel mills located in Braddock, Clairton, Duquesne, Homestead and McKeesport made the round trip to and from Brown's Dump to unload their contents. Loaded in teacup-shaped railcars, the molten cargo was transported to West Mifflin, continously day and night, then poured down the hillside like a river of volcanic lava.

As the slag pile grew into a hill, then a mountain, families and teenagers would park their cars on the roadways surrounding the slag pile to joyfully witness the red glow and smoke created by the flow of hot slag. Young and old alike would gasp in awe as the molten mixture lit up the night sky.

Vehicles would sometimes be lined up for a mile or more along Lebanon Church Road and Clairton Boulevard, especially in the evening. Many of these visitors had made the trip from other states just to witness the spectacle. Aside from the visual brilliance of the display, the slag dumping was a vivid representation of the might and power of the steel industry in the Mon Valley area.

Brown's Dump - West Mifflin Slag Mountain    Brown's Dump - West Mifflin Slag Mountain
For five decades, a continuous procession of Union Railroad trains brought molten slag to Brown's Dump in West Mifflin.

Slag is a by-product of the open hearth steelmaking process. When rock containing iron ore is melted in a furnace, the impurities separate from the iron and become a molten rock called slag. It is a hard, chunky compound of silicon, phosphorus, manganese and limestone.

The Brown's Dump heap began in 1913, when the Carnegie Illinois Steel Corporation, part of the U.S Steel Corporation, bought 410 acres of land as a dump site for the slag produced at the nearby Duquesne, Edgar Thompson and Homestead Steel works. Day in and day out the trains carrying their molten cargo made the trip to Brown's Dump, much to the delight of the curious onlookers. When dumping stopped in the late-1960s, the mountain had risen to over 200 feet and covered the equivalent of 130 city blocks. It became the largest man-made mountain in Pennsylvania.

In time, slag became too valuable to dump. It was discovered that slag used in concrete develops strength over a longer period of time. The once unwanted waste product of steelmaking could now be used in high performance concretes, especially those used in construction of bridges. The excavation of the slag became another lucrative enterprise.

Brown's Dump - Old Ladle Rail Car
An old ladle rail car that was found during the excavation of Brown's Dump.

In the late-1960s, after dumping stopped, U.S. Steel began selling off portions of the land for commercial development. A portion of the mountain was leveled off and a Murphy's Mart strip store opened. In 1976, construction of Century III Mall began. With 1.3 million square feet of retail space, Century III was the third largest enclosed mall in the world when it opened in 1979.

During excavation for the mall, developers uncovered an old ladle car and several "buttons." These mushroom-shaped chunks of metal were made of molten iron that solidified in the ladle cars and came loose during the slag dumping process. The buttons rolled down the hill with the slag and were eventually buried under the growing mound. Several of these buttons and the refurbished ladle car can be seen adorning the entrances to the mall property.

A Ladle Reamer.    Buttons.    A bucket from a ladle car.
A Ladle Reamer, used for cleaning ladle cars, a sculpture made of three ladle-shaped iron buttons,
and one of the buckets from the old rail ladle cars that stand outside Century III Mall.

The ground underneath Brown's Dump was once an old mining site that was abandoned in the early-1900s. In order to build a stable foundation for the mall, real concrete had to be pumped underground into the cavities before construction could begin. More concrete was said to be used in the filling of the old mines than was used in the mall itself.

Eventually, in the 1980s, U.S. Steel sold the remainder of its interests in the slag pile for further development. Today, numerous businesses crowd the base of the mountain, and several more were built on top, in the Century Square shopping center. On other parts of the mountain, the slag is being excavated at a rate of between 300,000 and 500,000 tons per year for use in roads, parking lots and high-grade concrete.

The entire complex that now resides on the old Brown's Dump slag mountain attracts millions of shoppers each year. This once remote valley has been transformed into a retail district that is a major contributor to the financial well-being of the Borough of West Mifflin.

Brown's Dump - West Mifflin Slag Mountain    Brown's Dump - West Mifflin Slag Mountain.
The slag mountain at Brown's Dump in 1969 (left) and again in 2012.

For those people fortunate enough to witness with fascination the dumping of the molten slag over the hillside in the 1960s and before, Brown's Dump will always be remembered as a place to witness the most spectacular continuous fireworks display in Western Pennsylvania.

The following are some remembrances of Brookliners who witnessed the fireworks:

"My aunt and uncle lived behind the dump in Pleasant Hills. As kids growing up we would always wait to see the slag being dumped from their backyard. It was truly magical." - Darcee B.

"I remember sitting at my grandparents house and watching the little train dump those red embers down that hill." - Patricia T.

"I remember the glowing hillsides, and sky too!" - Linda D.

"My grandpa took me to watch the slag dumps. I thought I was the only one!" - Judith A.

"Our parents would be driving us to the drive-in and we would be watching the glow on the way by." - Glen Y.

"I went out to the Redwoods or Yosemite after I graduated High School and saw something that they made a big deal of called a 'fire fall.' I remember thinking it was a tiny, poor imitation of our slag dump." - Carol W.

"I walked on top and there were many football size vats of slag that could be walked on. The orange crust was similar to the way ice can break. Underneath however was different, it was gooey." - Joseph C.

"Yeah, it looked like lava flowing down a mountain. Boy, those were the days. It was awesome." - Dave M.

"I can remember driving by there with my parents to watch the red hot slag getting dumped. Pittsburgh's own volcano action!" - Marilyn W.

"I remember when I was a kid in the 50s, being able to see the 'red glow' from these slag dumps after dark, even from a distance." - Michael C.

"Every Wednesday our family got into the car and drove out Route 51 to the pizza shop, then drove to OUR spot to watch them dump the slag. My dad even bought a convertible so we could all see!" - Joanne J.

"I remember going there as a child and watching the molten slag slowly roll down the hill. It was an awesome sight." - Eugenia B.

Brown's Dump - West Mifflin Slag Mountain

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