Explorer Rob Evans makes his way through brush, ferns and trees covering an abandoned 21-acre industrial complex.

Like Indiana Jones, Evans watches every step, prepared for the unexpected.

"It's not too overgrown. I've seen worse," notes Evans, an Auburn resident and former employee of Atlas Powder Company.

The lush, moist woods carry a sweet smell, along with the low roar of the rushing Little Schuylkill River as it rolls along its rocky course. But there's an invisible demon - the woods are filled with dangerous ticks.

The site of the Civil War-era H. A. Weldy Gun Powder Works of Tamaqua has given itself back to nature.

However, the ruins of the massive plant nestled in a sharp, secure valley are evident. Outcroppings of large square stones form a silhouette of mills, outbuildings, powerhouses and magazines used to store explosives.

Stone foundations that once anchored bridges are plain to see, as is a thick steel cable, one of a few that once spanned the river, carrying spectacular footbridges an amazing distance. The cable was wrapped around a boulder beneath ground level.

"It was something called a dead man anchor," explains historian and architect Dan Schroeder, Locust Valley. Schroeder has studied the site for years in a joint project with son Nicholas. He marvels at the engineering feats of the Weldy operation.

"There's a large boulder on the other side of the river where a steel rod protrudes from the bottom," he says, explaining how the support system enabled Weldy to build pedestrian bridges over the river.

Charred bricks, presumably from the powerhouse smokestack, are strewn around the land, resting where they fell when the stack was dynamited in the 1930s.

The haunting ruins of the H. A. Weldy plant will give up their secrets to those with enough courage to brave bug-infested brush. Thick walls can be found on both sides of the Little Schuylkill River. However, the side with the more impressive ruins is essentially a steep mountainside where the ruins cling to the cliff, making that section almost inaccessible.

With the 150th anniversary of the Civil War, there has been renewed interest in the Weldy plant, but negotiating the terrain is daunting.

"We've taken a lot of photos there," says Schroeder, who acknowledges the challenges accessing the sharp hillside but admits that the preserved history is enticing and begs for full documentation. "Maybe it's worth a book," he adds.

The Weldy plant featured a chasing house, riverside power houses, dams, brick smokestacks, magazines, coke ovens and various other outbuildings and infrastructure.

Today, high mounds of earth form the outline of the plant's original race, which channeled water from the river to a deep, narrow gully where it picked up speed and powered massive wooden water wheels. The race was so deep, perhaps 15 feet or more, that even after 150 years it presents itself a formidable man-made creation which nature has failed to obliterate.

"There was another one on the other side, too," says Schroeder.

Locals are aware of the plant's ghostly presence.

"We used to play there when we were kids," says George Pinkey. Pinkey is a Hometown native and former chairman of the board of supervisors where the plant is situated. (The plant identified itself with the town of Tamaqua but is located in Rush Township.)

Pinkey says the ruins of the buildings provided the perfect setting for young boys to play war games.

The isolated ruins belie what was a burgeoning explosives industry at a key time in America's growth. When Henry A. Weldy bought the small Huhn Powder Co. about 1862, he forged a business that produced not only gunpowder for the Civil War, but industrial explosives for the mining industry and a busy world that was blasting tunnels and changing the landscape.

Despite a relatively safe location alongside a river and wedged between high mountains, the plant suffered debilitating explosions in 1871, 1874 and 1878. Some were fatal and heartbreaking. The 1878 explosion of a magazine killed one worker and two little girls who happened to be playing nearby. The April, 1871, explosion blew up one of the mills and scared away investors. The accident led to a change in the firm when Lamont and Henry duPont of Delaware purchased an interest previously held by the Shindel family of Tamaqua.

(This may have represented the second phase of a takeover process because, according to historical accounts, E. I. duPont deNours & Co. had purchased controlling shares of the H. A. Weldy Co. as early as May 26, 1868.)

Explosions at the Weldy plant were so severe that spectators walked to the site from Tamaqua to check out the damage.

But each tragedy proved only a temporary setback. With Mr. Weldy at the helm, H. A. Weldy Powder Works always came roaring back. Weldy ran an impressive operation, assisted by son Charles, a bookkeeper who worked at the plant from 1875 to 1904.

At age 72, Weldy decided to retire. In 1902, moved back to his native Reading. The days of the Weldy plant were numbered. On June 12, 1903, another explosion hit, killing Jacob Kahler and Joseph Welsh, both of Mintzers.

A final disaster struck in 1906. The plant blew up, killing three men, one by the name of Dreisbach. Another victim is believed to have been Wilson Sassaman. One historical account describes a horrific scene: "Mrs. Samuel (Kate) Kramer often said after the severe blast, a cloud of black smoke rose high enough for her to see over the mountain between her and the blast. She said at the bottom of the black cloud there was an object which looked like a man caught in the midsection with feet and head down, dropping earthward and out of sight to her."

This time, the plant didn't come roaring back.

In fact, the powder mill was never rebuilt. Two years later, 1908, workers dismantled the H. A. Weldy Powder Co., and the real estate was sold to the Anthracite Water Company. The industrial site was abandoned.

But the powerhouse brick stack and some of the coke ovens stood intact well into the 1930s.

A powder mill stack was dynamited during the Depression years by James Shields, who used the old bricks for a chimney and for masonry work at a home he built in Barnesville.

In a sad twist of timing, Weldy's life came to an end a few months after his plant was dismantled. He died in his home at 135 Windsor Street in Reading on October 18, 1909. His body was returned to Tamaqua, where he was buried in Odd Fellows Cemetery.

A few short years later, World War I would break out with a surging demand for more explosives.

By then, Weldy and his plant were gone. But in 1913, a new, 2,700-acre explosives plant began operating in nearby Reynolds. It was called Atlas Powder Company, a major Tamaqua area employer for the next 80 years. In time, the H. A. Weldy Company was lost to history.

Today, nature's evergreens, laurel and vines hide the H. A. Weldy complex, now owned by the Commonwealth of Pennsylvania. A sign reads: "Pennsylvania State Game Lands." The river is visited by fishermen and kayakers.

But the adjacent woods and ruins are largely silent. The only remaining sound is the low roar of the river.

The hustle and bustle of a truly explosive industry has been lost to time.