My Personal Recollections...
The name of this ski area was first Big Valley and then Hahn Mountain.
I skied Big Valley and Hahn Mountain from around age four. The area closed for good in the mid 1980s when I was around 15 years old. Both my parents were ski instructors so we all spent a lot of time there. Big Valley was bought by the same guy that ran the Hahn fire truck company in Hamburg, PA, hence the name change to Hahn Mountain.
Looking from the lodge there were three main trails. The "Rim Trail" came down the left, "Big Valley" was in the middle and "Appalachian" was on the right. The lower half of each of these trails was called "Sitzmark", "Hawk's Landing" and "Grizzly", respectively. All of the trails had lights and snow making.
There were three lifts. There was a Hall T-bar located between Sitzmark and Hawk's Landing. The T-bar only went half way up the mountain. There was a Hall double chair lift between Big Valley and Appalachian. And there was a short rope-tow and beginner slope on the far side of the chair lift house called "Rooster Run". The T and chair were original dating from when the ski area was Big Valley. The rope-tow and beginner slope were Hahn Mountain additions. Hahn Mt. also lined all the lower slopes with pine trees.
And I remember some changes to the lodge when the area became Hahn Mountain. More decking was built around the outside perimeter and a small addition was built on the parking lot side of the lodge to house a new stairwell between floors. The old stairwell (which was removed) was located in the middle of the lodge near the cafeteria counter. The ceiling was removed exposing the roof rafters. This made the lodge feel more like a lodge. Several coal stoves were added for heat. There was a cocktail lounge area on the chairlift side of the building. The basement contained the ticket counter, rentals, restrooms, gameroom, ski patrol room and a short-lived ski shop.
Big Valley used individual snow guns, but Hahn Mountain used these enormous gas and diesel powered Hedco snow machines. I guess the machines didn't work out because they began converting back to small guns the year before they closed.
There were also a few unofficial trails that were sometimes available with enough natural snow and daylight. There was an easy narrow trail that we called "Proposed". It snaked around the back left-side of the mountain and came out between the Rim Trail and Sitzmark. From the top of the chair lift one had to climb a bit further up the mountain to find the entrance to Proposed. Proposed had such a shallow slope it was more like cross-country skiing. There was a short trail called "Foxy Lane", which was accessed by turning right at the top of the chair lift. The trail exited onto Appalachian. Foxy Lane was mostly abandoned during the Hahn Mt. era. I remember being able to gather enough speed on Appalachian to shoot back up Foxy Lane in the wrong direction. Finally, there was an unnamed slope directly beneath the chair lift.
Hahn Mountain is located north of Interstate 78. Take Rt. 143 north from Lenhartsville then turn left on Pine Creek Road. You'll see the remains of the ski area on your left just before reaching Gun Club Road.
After Hahn Mountain closed down my parents and I moved on to Heidelberg/Blue Marsh ski area. I became a ski instructor too, but gave up skiing for good after a few more years. Blue Marsh is now gone as well.
One of my fondest memories of Hahn Mountain is pinball! There was a small gameroom in the basement of the lodge that included a 1979 Bally Star Trek pinball machine. I now have a pinball collection including a Star Trek of my own. I also spent a lot of my childhood at the nearby Wanamaker, Kempton & Southern steam railroad. As an adult I'm now a volunteer at the railroad and sometimes drive by old Hahn Mountain.
If you happen to have a picture of the old Hahn Mt. gameroom, please contact me.