Brown's Dump in West Mifflin (circa 1990). 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.
This is before the building of the Walmart atop the hill and Century III Plaza at the base.

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

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 disposal site for the huge amounts of slag produced at the nearby Duquesne, Edgar Thomson and Homestead Steel works.

For over fifty years, Union Railroad slag trains from the mills made the trip to Brown's Dump to unload their contents. Locomotives pulling teacup-shaped railcars arrived continuously, day and night, to pour their molten cargo down the hillside in what resembled a river of volcanic lava, much to the delight of curious onlookers.

  
A long string of ladle cars dump their molten cargo at West Mifflin's Brown's Dump.

Slag is a waste by-product of the smelting process of making steel. When rock containing iron ore is smelted in a furnace, the impurities separate from the iron and become a molten rock called slag. It is a hard, chunky compound composed of silicon, phosphorus, manganese and limestone.

As the years went by the slag pile grew into a hill, then a mountain, the height of which further enhanced the volcanic spectacle.

Families and teenagers would park their cars on the roadways surrounding the slag pile to witness the glow and smoke created by the long red flows of lava. 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.

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

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.

When dumping stopped in the late-1960s, the mountain had risen to over 200 feet and covered the equivalent of 130 city blocks. It had become the largest man-made mountain in Pennsylvania.

U. S. Steel began selling off portions of the land for commercial development. A section of the mountain was leveled off for construction of a Murphy's Mart strip store and Century III Mall opened in 1979. Other retail outlets soon followed.

An old ladle rail car that was found during the excavation of Brown's Dump.

During excavation for the mall, developers uncovered an old ladle car, some other slag hauling relics 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. Several of these buttons, relics, and the refurbished ladle car can be seen at the entrances to the former mall property.

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.

     
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.

In an interesting twist of fate, it was discovered that slag used in concrete develops strength over a longer period of time. The once unwanted waste product of the steel making industry is now used in high performance concretes, especially in bridge construction.

Excavation of the slag became a lucrative enterprise, and Brown's Dump found new life. For a while, in preparation for further development, between 300,000 and 500,000 tons per year for use in roads, parking lotsand 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.

  
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.

"This was entertainment for us as kids ... a drive to watch the flowing slag as we parked along the road in the 1940s. It was family time" - Mary G.

"There were two drive-ins out on Route 51 and we'd have our fingers crossed hoping for a live dump while we pasted. Impressive." - Jack S.

"Remember it very well! In the winter when it snowed the hot slag would explode and hiss and smell...what a show!" - Carol K.

"I remember riding in the car with my parents and seeing the slag being dumped. It was our entertainment." - Kathleen C.

"I so remember this. My dad would take us up to Jack's Bar on Route 885 and we would sit in the back dining room eating our chips and drinking pop. It was so pretty. Oh the memories as kids." - Mary N.

"One of the many amazing final stages in the production of Pittsburgh’s once Fortune 500 industries." - Steve R.