The “Bonin” (Pop) cave.
Location and access:
The cave is located 2.5 km southeast of the village of Krushuna (Krushuna waterfalls), Lovech district. The altitude of the entrance is 254 m in the slope of Slivov dol, at the periphery of Devetashko Plateau, Middle Forebalkan.
Until 1972, only the stretch to the river by Ivan Lichkov was studied. In the period 1974-75 the cavers from the “Studenets” club at a tour. “Kodolina”, Pleven studied and mapped 2753 m, in 1978 during the international caving expedition “Drujba’88” were mapped 133 m. after the half-field along the river.In the period 1985-87 the cavemen of the dwarfs from the Studenets club crosses four siphons along the river and examines the next gallery and maps another 461 meters and the total length of the cave rises to 4015 m. After 1990 the same team passed the siphon to the river and studied 515 m. the new parts of the cave reach its current length – 4530 m ..- 7th in length in Bulgaria
Description of the cave:
It is formed in lower limestones – Devetashka chalks with apttic age of the monoclinic chorus of the same name. NV at the entrance 254 m.
The cave is two-storey. The entrance has a size of 7.5 x 3.8 m. The first floor is a horizontal gallery with a total length of 280 m. During the summer season it is usually dry, the floor is loamy, in some places covered with gravel and gravitational material, almost without formations. In this part the rocks are highly corroded and eroded. Two halls follow each other. Dried and their floors covered with clay. About 25 m. Of them a 15 m long, 10 latitude and 4 m deep lake. It is crossed by boat.
Note: There are years in which the gallery is filled with water near the entrance.
On the opposite side of the lake there is a threshold of 8 m high. When it is dry the climb is not difficult. It is more convenient for him to provide a ladder -10 m or a rope about 15 m. After climbing the plinth, it falls into a small hut with beautiful but dry sink lakes with a depth of 40 cm. Beautiful petrified waterfalls complement the interior. Here is one of the beautiful places in this cave. After 30-40 m it goes to the underground river, from where the penetration takes place with boats. To the right of the river, after about 350 meters, a siphon is reached. Sifona and the next three were passed in July, August 1985 by Ilko Gunov, Milen Dimitrov, Valentin Chapanov and Alexander Mihov from the cave club to the Kailushka Valley in Pleven. The first siphon on the color-coded waterway to the Waterfall cave is 5.5 m long and 3.6 m wide. A prominent blanket with an airspace of 1.6 m is coming into a small dome. After it begins a new 6m long siphon, it enters a hall with a sinter barrier in the middle and a height of 30 cm. It enters into a new 30m long siphon, which is a channel with a depth of 8-9 m. It goes into a large a spacious hall with a series of beautiful open-air thresholds, some of which are open underneath, while others flow through the water. On the ceiling, there are many beautiful shapes covered with calcite crystals, which fly like frost when blowing. It enters into a new 35.5 m long siphon, we go into a large hall at the beginning of which there is a very beautiful waterfall in the shape of a glass. Further, there are two more thresholds drilled below, which are located in a lake measuring 3x10m. then the gallery continues with a damp clay floor and not far from the edge of the lake there are two sheep. The smaller is impossible to penetrate and the entry is through the big one. Going down is done on a fireplace using a rope. Its depth is 15 m, and at the bottom it widens into a bell. The two plumes serve as spillways when raising the water level in the nearby lake. This is evident from the thick layer of clay that covers the lower part of the plumb line. After the plumbing, the gallery is narrow and low, after 10 meters there is a hole on the floor where the incoming water flow flows. It goes on, and it is not long before going to a gallery perpendicular to the direction of movement. On the right, three thresholds are crossed over the water, the first one with a height of 2 m, the second one with a height of 1 m, and the third one with the flowing water on them, represents a beautiful view.
After the lake upstairs, the gallery continues to dry. The height is between 2-2.5m. and there are small puddles on the floor. Approximately 70 m from the two plots have another, where the spotlight illuminates the bottom. After another 100 meters, there is a new small plumb line on the right. At the same time, the gallery is lowered to a small stone covered with mud. Due to lack of time, no attempt was made to clear the stopper. They leave for another time and the plumps leading down and downstairs. The total sum of mapped galleries and siphons is 461 m.
To the left, along the river, the cave is about 1300 meters long. Boat penetration in this area is a real pleasure. Beautiful dome-shaped stalagmites, shields, ribs and all this, a man enjoys the boat. You can even catch sea sickness, say jokes. The gallery is constantly lurking. Clear old water levels are clearly visible. faces are almost everywhere. And the evolutionary domes, which are not small in the cave, are almost always in straight shapes and pronounced.
Not less than 12 sink barriers, they block the lake, most of them are not fed by the water, it is necessary to get off the boat and transfer to the next section. In many places, care must be taken because there are sharp knives in the water and covered with water that can crack the boat. In the middle of the waterway in this gallery (not far from each other) there is plenty of dripping water from the stalactites. In other parts of the cave, such phenomena have not been noticed. Depth of water varies from 1.20 to 2.50 m. The cave ends with a siphon. Rich in secondary formations.
There is a 515 meter long gallery along the siphon to the river. The cave is part of the drainage system of the karst waters of the plateau.
The underground river of the cave continues its underground road through the waterfall cave Waterfall (with a flow of 20 liters). This was proven by the coloring of the water in 1988 during the expedition carried out in 1978.
In order to penetrate the cave, appropriate clothing for water caves is needed, good lighting for 12 hours – carbide or hermetic and reserves to it, boats, 10m. ladder or 15 m rope.
The fauna is represented by 14 species of animals, of the troglobionites are the side-swarming crab Nifargus ablaskiri georgievi, the spider Porrhomma profundarum, the water moth Trichoniscus garevi and the centipede Typhloiulus (T.) georgievi.