Spring Valley Caverns



As I rounded the corner the water became deeper, and the room suddenly took on an eerie feel. Aided by the chest deep water, I felt almost buoyant in my thick rubber-like wetsuit. And while the water was slowly finding its way into my wetsuit, my eyes were also slowly scanning the room, searching for a way beyond. Waiting for Tim, I shut my light off and allowed my body to float in the pitch-black expanse. Soon I became enchanted with the musical sounds the ceiling droplets were making as they struck the surface of the calm spacious pool. A few moments later my trance-like daze was interrupted by the sounds of sloshing water and glimpses of light. “You hold your breath and dive under the wall,” Tim said nonchalantly.

And so here I was, on a pleasant summer day in July 2006 in a S.E. Minnesota cave known as Bat River Cave, with Tim Stenersen. Tim thought it was important that I inspect the terminal sump at the end of the cave for exploration possibilities, and who am I to refuse?

After passing by an array of lush green moss carpeted rocks alongside a rippling meandering stream, a large natural rock arch gallantly announces the cave mouth. This harmonious arrangement merges to create an imposing picturesque cave setting. Bat River Cave is located in the same general vicinity as Tyson Spring Cave, which also has a crisp clear stream flowing from the base of an impressive limestone bluff.

But none of that mattered to me now, as I plugged my nose and dove under the wall, hoping I would surface in a large air filled passage like Tim had promised. True to his word, it was a safe and short journey, and before long Tim, cave diver John Preston and I strolled through almost one half mile of stimulating cave passages before reaching the “end” of the cave.

Other attempts had been made in the past to dive through this sump at the end of the cave but the conditions were never right, and subsequently the cave was rubber stamped as “pushed out.” Because of this classification, and the fact that the natural water filled passage near the entrance served as a cave gate, this cave has seen very few visitors.

Preston and I were not overly impressed with the terminal sump but nonetheless he decided to gear up and give it a serious look. While Preston was attaching his weight belt, air tank and assorted hardware I explained to Tim that there are people who make things happen, there are people who watch things happen, and there are people who wonder what happened. I admitted that my problem was that I fit squarely into the first category, and because of that I have nearly lost my life untold times. I have had my share of near-drowning incidents resulting from cave diving, the memories of which remain vividly etched in my mind. My last sump diving foray, about 1½ years ago, took place in a large Fillmore County cave known as Goliath’s Cave. Preston had managed to find an extensive dry cave segment after diving a sump at the “end” of the cave. Soon thereafter I lost all sense of reason, donned underwater gear, and after groping through a maze of pitch-black subterranean passages I surfaced into the newly discovered section. We walked for one third of a mile before turning back. On the way back out, under the sump, my tank became detached from my harness clips and floated up into a tall fissure, almost severing my airline. After correcting that situation I continued along the labyrinth of twists and turns and almost became entangled in the lifeline. As if that wasn’t enough excitement, I was startled to encounter large rocks that had shifted and were preventing my return. After managing to shove them aside in total pitch blackness I inched forward and was reminded why I swore off cave diving. Heck, using high explosives in unstable rock zones is child’s play compared to this.

No, this time around I chose to play it smart and be one of those who watched things happen!

After my discussion with Tim drew to a close, Preston struggled to squeeze his body between the rock ceiling and sandy floor, and to my surprise he completely disappeared! The dive line spool that I was clutching steadily unwound, then would stop, and then resume. Eventually I felt three distinct tugs on the line. That was my signal that Preston had surfaced. Somewhere.

Tim and I sat in the safety of our spacious comfortable passage speculating what Preston’s predicament was. As the minutes slipped by, our speculations encompassed all sorts of predicaments and possibilities. And as the hours painfully drug on Tim asked in a reserved tone “who we should contact in the event Preston does not surface?” “Me” I responded, “we will have to trek all the way out of the cave, haul in the backup gear and I will have to find him. I don’t think anyone from the 911 crew will be volunteering any time soon.”

I began to run through all the options in my mind. What if I encounter his lifeless body as I am groping my way through the inky black maze? What if his body is blocking the passage? What if I surface into a dry cave passage and eventually find his body at the bottom of a deep chasm? What if….

By now it was dark outside and surely our surface watchers, Dave Gerboth, Charlie Graling and Ted Ford were getting a bit anxious. I was beginning to run through the contingency dive plan in my head and did not like any of it. Tim was showing early signs of hypothermia and it really didn’t surprise either one of us when we both spontaneously blurted out “Come on Preston!” I had been hovering over the black pool, gripping the dive line for any sense of movement, when finally I felt a faint twitch. Then another. Soon there were definite tugs on the line and Tim and I knew Preston was retreating and all would be well. What a relief.

Almost without warning, Preston’s head popped up through the black abyss and at once proclaimed he had discovered a major section of cave. He reported that he had traveled through the under water sump passage and had surfaced near a major waterfall, which cascaded down the wall of an immense room which he estimated to be 35 feet wide, 50 feet long and 40 feet tall. With a great amount of difficulty he successfully scaled it and went on to explore large upper level walking passages lined with hundreds of bats and thousands of rare and unique formations. After determining that the cave continued ahead without closing down he retraced his journey out.

I sat there for several moments, almost numb, and felt like a cat trapped behind glass while mice danced the night away on the other side. “No matter what,” I murmured to myself “I will be diving this sump. End of discussion”


Again I reasoned that if I scrupulously prepared for such an adventure that it would cut my odds of dying by some small margin. In my mind and heart I wanted to believe this, but past experiences have proven otherwise. Nonetheless I spent countless hours that summer in my swimming pool, doing such odd things as swimming several lengths without taking a breath and practicing all kinds of maneuvers in the dark while submerged in the deep end. By now it was apparent that my wife and kids were on to me. Hmm.

By the end of October I felt I was “ready.” I had gone over every “what if” scenario thousands of times. My 14” x 10” dry box was outfitted with essential survival gear and the well driller’s cell phone number was given to Clay Kraus just in case. If a horrible situation occurred beyond the sump an access hole could be drilled into the huge room. Since the original part of the cave had been surveyed previously I surmised it would be fairly easy to locate the vast air space just beyond the sump for an access hole. In addition to all this, back up divers were on call. One had been in the original section of the cave before and had assisted with gear transportation to the dive site.

In certain situations there is safety in numbers, so I called on my friend Phil Gemuenden to join Preston and I for this monumental and historical exploration journey. Like Preston, Phil is extremely qualified and well seasoned.

The first thing I did was bolt a large diameter climbing rope to the wall above the sump and had Preston take the lead end through the sump where he secured it to a large irregular shaped rock. Even though my fear about a line entanglement was now at rest I still had to deal with all the other “what if” fear factors. But as I slipped my face under the pitch black water, all external stimuli and preconceived fears instantly vanished. My mind was now focused and directed to the senses of hearing and touch. The sounds of each inhale and exhale seemed to take up every available space in my brain. My air tank scraped and screeched along the ceiling as my belly wriggled along the coarse sandy floor, feeling for more clearance. Even though the height of this subterranean passage was low, it was considerably wide. Wide enough so that I was well aware that if I lost the line I would wander around in the inky blackness, frantically and hopelessly searching for the narrow single escape point until my air supply ran out.

It was no wonder my entire being was now concentrating on clenching the rubber air piece firmly in my mouth and deliberately gripping the hand line while simultaneously allowing it to glide through my fingers. It is never a good day when your mouthpiece gets wrenched from your lips after the airline snags on a passing projection. And the day really turns rotten when you realize you have lost your guideline while frantically searching for your air supply.

After what seemed like eternity I felt the water pressure release it grip on me as I rose higher and higher until I broke the surface. As I sat on a large limestone slab removing my gear, Phil’s head popped up out of the water like a Jack in the Box. All thoughts were now directed towards the roar of the waterfall, obviously located nearby. As Phil and I entered the great room and approached the falls we were both in awe. Preston stood at our sides, just grinning from ear to ear. Soon a tactical debate ensued regarding how to safely scale it. Preston had suggested that we free climb up an exposed wall to an ascending set of very narrow ledges and then carefully make our way to the falls along the 4-inch wide catwalks. Even though that was his original discovery route I deemed it much too dangerous. I could see where chunks of narrow ledges had fallen away from his previous balancing act and didn’t even want to think about how we would get one of us out of the cave with a broken neck. Instead we were able to assist each other up the very center of the falls to the upper level passage, similar to the method ants do to bridge gaps.

The view from the top edge of the falls was as spectacular as it was from the base. Especially notable was the huge hole the water had cut right through solid rock before crashing down into the blackness of the room below. We unpacked our survey gear and began to venture along the main upper level trunk line. I was honored to be the lead tape man. Phil held the other end of the tape and read the compass and length readings back to Preston, who recorded the information. As we began our journey I was astonished to see that the average ceiling height was 20 feet. Everything was exactly as Preston had described it, and more. Eventually we surpassed Preston’s turn around point and suddenly the ceiling dropped down, forcing us to move ahead on our hands and knees. The passage was still very wide, and as we wove through masses of low hanging formation clusters I wished out loud that the cave would resume its former prominence.

Then, just as suddenly as the ceiling height had diminished, it rose once again. Onward we strode, and occasionally we would pause briefly to comment on a spectacular formation or a cluster of bats. Many hours had slipped by without anyone noticing, and when the question was asked “what time was it?” Preston shouted out “one mile!”

We had surveyed over one mile of virgin cave and had passed unexplored side passages but I was still revved up for more. The ceiling height had once again dropped at the one-mile mark, and while Phil and Preston took a well-deserved break I moved forward along the low wide passage. After about three hundred feet I was well out of earshot and thought it prudent to return. I pulled an identification marker (a poker chip with the date and my initials) out of my pocket, tied it securely to an overhead formation and regrouped with Phil and Preston. They were ready to retrace our journey out of the cave system, to which I prudently agreed.

I have few recollections of the exit trip. Maybe because I was obsessed with the thought that (like a game of Russian roulette) this may be the time I was going to drown in the sump. Or could it have been that I was completely numb from such a stupendous discovery? I do remember staggering through the woods late that evening, and encountering Clay Kraus with his blinding searchlight asking “Is everything O.K.? It’s very late.”


The sights and sounds of that epic journey were imprinted into my very senses and I was driven to return to this amazing cave system. Burning questions needed answers. Where was the cave in relation to the surface? From where was the great number of bats entering the cave? Where did the side passages go? How large would this cave system be after exploration? Where was all the water coming from?

Since Preston had accepted a sudden and unexpected job promotion in Ohio, unfortunately my questions were put on hold. Not only did my access ticket disappear, so did the survey data. However, Preston reassured me that the survey data was safely packed away-somewhere, and that he would plan on returning as soon as he could so we could reenter the cave.

Fall came and went.

Winter came and went.

Clay Kraus and I spent some of that time trying to decipher the survey data that Preston had eventually sent, but the more we knew, the more questions we had. Questions that only another trip into the cave could answer. It was now May of 2007. Spring had more than sprung. When my long time friend from Wisconsin, Dave Wysocki, sent me an e-mail that casually mentioned the words “cave diving” I honed in on the phrase like a beacon in the night. Soon I was corresponding with his cave diving instructor friend Tami Thomsen. Tami’s worldwide reputation and qualifications justifies her as the who’s who of diving. The hard cold fact was that the only doorway into the new section was through that pitch black water filled abyss, and thankfully Tami offered to be my mentor and guide.

Before we knew it Dave Wysocki, Dan Pertzborn, and Tami and I were making our way through the original portion of Bat River Cave laden with dive gear. Dave and Dan had offered to assist with the project but would not be diving the sump. When Tami reached the sump she was so completely comfortable and confident with the dive plan that I actually lost most of my fear factor. I opted to go through the sump first because I figured that the clear visibility would marginally cut the risk factor. Tami would follow with the gear in tow after I reached the other side.

Wow. The passage began in crystal clear visibility and I could see the white sandy floor stretch out of sight. As I moved forward, gliding my fingers along the guideline, which had settled in the sand, I saw the silt gently slough off of it, creating a mild haze. I did my best to stay ahead of the silt clouds and noted that the passage took a bend up ahead, which I had not sensed previously. As I rounded the bend and continued forward some distance I felt my ear pressure begin to relax and made note that I was rising. I tilted my head and scanned for the typical mirrored surface that one customarily sees when popping up into air space. Instead, almost without warning, my head abruptly punched right up into the air space. I had forgotten that the water surface on the other side was covered with organic debris, i.e., tiny sticks and plant matter, which effectively blocked out any light penetration.

Soon I felt tugging on the line and knew Tami was on her way. After a period of time I began to see her bubbles surface, but then all of the sudden they disappeared. That could have only meant one of two things. Either she had drowned or she had retreated. Terrible thoughts began to run through my head. I removed my tank and harness and sat on the edge of the sump, staring into the water. After scaring me half to death her bubbles finally appeared again. She rose up out of the water suddenly, pulled her mask away from her mouth and blurted out “the gear is wedged between the rope and the passage curve.” Just as quick as she had risen, she was gone again. Eventually she returned, towing both large dry boxes and one bulky heavy pack behind her. I was more than impressed, and obviously very thankful our return exit was now clear and our guideline was in place.

When Tami saw the falls I am sure she was wondering what kind of gizmo I had stashed in the packs so we could scale it. I use the word “wondering” because it was May, and the water was thundering down the falls, making communication almost impossible. After failing our repeated attempts to duplicate the method that Preston, Phil and I had used to scale the falls, I was finally able to secure webbing around the arch above the falls. With water crashing down on top of us, Tami fashioned footholds in the webbing, and soon we conquered the beast.

With the survey data in hand, we made our way deep into this superlative cave system, searching for several good sites to conduct a radio survey location. Clay Kraus and Charles Graling were topside with the receiver, and since it was getting very late, I figured they were probably roaming half way around Fillmore County, wondering where we were. Towards the “end” of the known cave system a suitable site was chosen and the radio gear and antenna was unpacked and placed in a large intertube that we had inflated. After successfully connecting with Clay and Charlie, Tami and I hiked deeper yet along the main passage and elected to conduct one more reading. This time we chose a site along a stretch of borehole passage with only several inches of water coursing along the floor. Even though there were electrical problems with the transmitter-which involved getting shocked, having to rest one ear on the stream floor while holding several connectors together and attempting to shield the open case so water droplets didn’t fry the exposed electronics, the reading was successfully transmitted and received. While all of this was going on I wondered what was going through Tami’s head but I thought it best not to ask.

It was late, and reluctantly it was time to head back. Along the way we marveled at the unique and pristine formations, pondered the source of the bat entry and made note of unexplored side passages. What an astonishing discovery. One that I made a commitment to explore, study and protect.

In fact, as I exited this wondrous geological treasure, I knew two issues were extremely important, yet difficult to legitimize their coexistence. First, a safe and more accessible entrance to aid research and exploration, and secondly the preservation and protection of such a significant geological discovery.

Today I am proud to officially announce that I (The Minnesota Cave Preserve) have purchased 231 subterranean rights to this cave system along with sufficient surface acreage and have created a safe man made entrance into the cave below.

I feel a coexisting solution has been reached, by offering safe unlimited scientific and exploratory possibilities while providing perpetual protection for this delicate natural phenomenon.

Such an event of this magnitude requires many thanks. I personally want to thank everyone mentioned in this article, especially Clay Kraus, who orchestrated the logistics of this project and was paramount in turning this dream into reality.

John Ackerman

Read the HISTORY


Bat River Cave History