altaskier
Contributor
There are a few trip reports here regarding the Bonne Terre mine, but I thought I'd add my own. I went there this past weekend with a fun group organized by Susan of Chicagoland Four Seasons Scuba Club/Chicago Scuba Meetup. Susan arranged for our group to have the hospitality room at the Super 8 in town, and to use the divers' lounge area at the mine with chili and snacks set out between dives, and those were great extra touches! I did three dives on Saturday, and two on Sunday.
As others have reported, they have 24 trails that you have to do roughly in sequence. Before trail 1, you have to watch an old video reminding you of the basics of scuba diving (about 15 minutes), and get a briefing on the dive. You then head down to the mine, walking down some 60-70 steps and then a sloping path down into the mine (I didn't find it to be too bad). The main entrance room is huge, with very large open spaces, so it doesn't feel at all claustrophobic. There's a wooden platform with benches and tanks, and a floating platform edge for jumping into the water, and floating steps with a handrail for coming out. After grabbing a tank and setting up your gear, one of the staff check out your kit to see that the regs and inflator are working etc. For dive 1, you do a surface swim to a room with a floor at about 20 feet, and then you have to demonstrate air-sharing with a buddy, and clearing your mask. You can have 10 dives in your log or 1,000 - they want everyone to demonstrate this.
The dives are led by a guide, with usually two safety divers bringing up the rear of the group. Those three staff divers have blue glowsticks on their tanks, while you get a green glowstick. The leader will usually check air once or twice during the dive, and those who are below a certain threshold will ascend and do a surface swim back, led by one of the safety divers. On trail 1 you're not allows to use your own light (so that there is no confusion on communication from the dive guide), but you can bring a light on subsequent trails. Also, the water temperature was 58 F on our visit, and it stays pretty constant year-round. The staff all use dry suits, and about a third of our group was also diving dry (including me). Nearly all the tanks had yoke valves, but they did have just a few with DIN valves. Nitrox is available, but the surface intervals are long and since you have to dive in a group with non-nitrox divers I didn't see any added value in using nitrox so I didn't fork over the extra money. And speaking of extra money, I humped my own weights down with my gear at the start of my two days, and brought them back out at the end of two days; otherwise you must pay something like $17/day to rent weights down in the mine. Also, those in our group who don't own their own gear rented from their local Chicago area dive shop, so we didn't have any chance to evaluate the quality of the gear they rent at Bonne Terre.
As far as the diving goes, I found it to be a unique and neat experience, and it got especially interesting after the first two dives were out of the way. They cavern has bright lights at various places throughout, so in many cases you are in a reasonably well lit room. In other places you have very little ambient light, and there are some rooms and passages where there's no light at all except what you bring yourself. The topography of the mine is really neat; sometimes you're swimming between these huge, towering rock pillars in a scene that reminded me a bit of the fake-submarine scenes in the movie "Hunt for Red October." Other times you're going through narrow passages, and here and there you find mining artifacts like pick axes, ore cars and rails, remains of an elevator, X marks on walls where blasting was planned...
The place is more like an underground lake with passages cut between rooms (and sometimes at multiple levels), so it's not as unforgiving as cave diving. You may sometimes be guided through overhead regions (more and more I guess as you progress through the trails), but on the dives I did we were nearly always within 100 feet or so of a location where one could rise to the surface and do a surface swim back if necessary.
At least to a first-time visitor, it's not always easy to figure out which direction leads you back to the dive dock, so it's quite understandable that you are required to dive as a group. This can sometimes be a bit of a pain, with the possibility of literally bumping into your fellow divers (depends of course on the experience and politeness of the group) and occasional waits for the group to go in turn through a narrow passage. Still, I can understand their need to have groups stay together with safety divers in tow so as not to get lost! Also, unlike a coral reef where the name of the game is to go slow in order to see all the hidden critters, here you tend to haul ass around since you have to swim from the dive dock through to some other area in the mine and work your way back again.
I took some pictures through the weekend; a link is here. I ended up using only ambient light, because it seemed the best way to convey the feel of the place. After some experimentation, I ended up going into manual mode with a shutter speed of 1/30th of a second (in order not to have blurring from camera wobble), wide open F2.0 aperture on wide angle, and ISO 1600 or 3200. I also went to manual focus on infinity, so as not to have the auto focus hunt around when it was dark. This was on a Canon S95 (saving files in raw mode) in an Ikelite housing.
All in all, it was a neat diving experience. Yes, diving in a crowded group was a bit weird, but I can understand it from a safety point of view. More importantly, the scenery and feel of the place was quite unique, and for this timid soul this is the closest I'll ever come to cave diving. I thought it was a cool trip!
As others have reported, they have 24 trails that you have to do roughly in sequence. Before trail 1, you have to watch an old video reminding you of the basics of scuba diving (about 15 minutes), and get a briefing on the dive. You then head down to the mine, walking down some 60-70 steps and then a sloping path down into the mine (I didn't find it to be too bad). The main entrance room is huge, with very large open spaces, so it doesn't feel at all claustrophobic. There's a wooden platform with benches and tanks, and a floating platform edge for jumping into the water, and floating steps with a handrail for coming out. After grabbing a tank and setting up your gear, one of the staff check out your kit to see that the regs and inflator are working etc. For dive 1, you do a surface swim to a room with a floor at about 20 feet, and then you have to demonstrate air-sharing with a buddy, and clearing your mask. You can have 10 dives in your log or 1,000 - they want everyone to demonstrate this.
The dives are led by a guide, with usually two safety divers bringing up the rear of the group. Those three staff divers have blue glowsticks on their tanks, while you get a green glowstick. The leader will usually check air once or twice during the dive, and those who are below a certain threshold will ascend and do a surface swim back, led by one of the safety divers. On trail 1 you're not allows to use your own light (so that there is no confusion on communication from the dive guide), but you can bring a light on subsequent trails. Also, the water temperature was 58 F on our visit, and it stays pretty constant year-round. The staff all use dry suits, and about a third of our group was also diving dry (including me). Nearly all the tanks had yoke valves, but they did have just a few with DIN valves. Nitrox is available, but the surface intervals are long and since you have to dive in a group with non-nitrox divers I didn't see any added value in using nitrox so I didn't fork over the extra money. And speaking of extra money, I humped my own weights down with my gear at the start of my two days, and brought them back out at the end of two days; otherwise you must pay something like $17/day to rent weights down in the mine. Also, those in our group who don't own their own gear rented from their local Chicago area dive shop, so we didn't have any chance to evaluate the quality of the gear they rent at Bonne Terre.
As far as the diving goes, I found it to be a unique and neat experience, and it got especially interesting after the first two dives were out of the way. They cavern has bright lights at various places throughout, so in many cases you are in a reasonably well lit room. In other places you have very little ambient light, and there are some rooms and passages where there's no light at all except what you bring yourself. The topography of the mine is really neat; sometimes you're swimming between these huge, towering rock pillars in a scene that reminded me a bit of the fake-submarine scenes in the movie "Hunt for Red October." Other times you're going through narrow passages, and here and there you find mining artifacts like pick axes, ore cars and rails, remains of an elevator, X marks on walls where blasting was planned...
The place is more like an underground lake with passages cut between rooms (and sometimes at multiple levels), so it's not as unforgiving as cave diving. You may sometimes be guided through overhead regions (more and more I guess as you progress through the trails), but on the dives I did we were nearly always within 100 feet or so of a location where one could rise to the surface and do a surface swim back if necessary.
At least to a first-time visitor, it's not always easy to figure out which direction leads you back to the dive dock, so it's quite understandable that you are required to dive as a group. This can sometimes be a bit of a pain, with the possibility of literally bumping into your fellow divers (depends of course on the experience and politeness of the group) and occasional waits for the group to go in turn through a narrow passage. Still, I can understand their need to have groups stay together with safety divers in tow so as not to get lost! Also, unlike a coral reef where the name of the game is to go slow in order to see all the hidden critters, here you tend to haul ass around since you have to swim from the dive dock through to some other area in the mine and work your way back again.
I took some pictures through the weekend; a link is here. I ended up using only ambient light, because it seemed the best way to convey the feel of the place. After some experimentation, I ended up going into manual mode with a shutter speed of 1/30th of a second (in order not to have blurring from camera wobble), wide open F2.0 aperture on wide angle, and ISO 1600 or 3200. I also went to manual focus on infinity, so as not to have the auto focus hunt around when it was dark. This was on a Canon S95 (saving files in raw mode) in an Ikelite housing.
All in all, it was a neat diving experience. Yes, diving in a crowded group was a bit weird, but I can understand it from a safety point of view. More importantly, the scenery and feel of the place was quite unique, and for this timid soul this is the closest I'll ever come to cave diving. I thought it was a cool trip!
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