(Note: Beamshots below all this text for those that want to skip ahead.)
EDIT: Links to newer posts with photos:
Return Trip November 2015.
Well as promised here is my thread dedicated to my adventure in working in an old inactive underground mine. Yes, I got paid to play . . . ahem . . . test out different flashlights. I don't usually get to work underground (due to the usual safety training requirements for active sites) so this was perhaps a once in a lifetime opportunity. (I'm a land surveyor.) I had also just finished up the modded Maglite I built specifically for this type of underground use - a 3C Mag with a neutral white XP-G R5 and 3 mode (L-M-H) Nangj 1.4A driver intended to run on (3) 4500mAh C NiMh cells. So this was also a perfect opportunity to test the light myself and get firsthand experience with their underground working conditions (minus the usual truck traffic with the dust). I originally posted here looking for recommendations for a flashlight for this specific use. (This is actually what brought me to BLF.)
A little about the site. It's an old inactive limestone mine. Corridors are approx. 25 feet wide with 10 foot ceilings, not cramped at all. The mine shut down it's operation sometime in the 1950's (I found wooden boxes that were labeled as "Atlas Blasting Powder" which were dated 1950 to 1951). None of those boxes were nice enough to bring home as souvenirs. A mushroom farm operation took over the mine in the 1960's and has maintained the mine ever since. Areas of the mine closest to the farm's "plant" building are used for mushroom farming, equipment storage, etc. . . They also make use of the mine's cool air (49 degrees the days we were there) along with the mine's ventilation system. And I tell you what - you've NEVER experienced darkness until you've been back into a mine and shut off all your lights! And at times it was the most silent place I've ever experienced! It was also like a time machine; I felt like I was in a world that had remained unchanged since the 1950's. We were able to drive our company truck into the mine and we also had golf two gas powered golf carts with us. We just couldn't leave engines running for longer than needed.
An interesting fact: The soon to be released (May 4th) movie "The Avengers (2012)" (Links http://movies.yahoo.com/movie/the-avengers-2012/production-details.html & http://www.imdb.com/title/tt0848228/) had a scene filmed in the southern mine. I am told it is the opening scene. It's supposedly a car chase scene with car crashes.
I had one weird experience I have to tell you about: Being around 49 degrees you can see your breathe. I was at one location where when I breathed, my breathe would just hang there in front of me and not move. I could then move to the side and look around my breathe. It was weird! Must have been very little airflow in that area.
About the modded 3C Maglite: I didn't use this light much myself because I gave it to the other crew members to test out and get a feel for using it (ie. if it was too heavy, too bulky, not bright enough, etc. . .). Therefore I don't have many comparison shots with it. I don't own NiMh C cells, so I ran it on AA NiMh's in C cell adaptors (SoShine's from DX). They were brand new 2300mAh Energizer's (non-LSD type - green top "made in Japan") and I calculated to expect around 1.5 hour runtime on high (2,300/1,400 = 1.64 hrs). I had 6 more AA NiMh's in case we needed them. Surprisingly the Energizer's lasted all day (we spent about 9 hours underground each day, and the light was only on when needed). I am not sure which mode the other guy was using nor how long he had it on (he was way ahead of me on foresight duty). I had been aiming for a light with about 6 to 8 hours runtime on high and now realize that's not necessary. I had thought I'd need to get two sets of C NiMh's to be sure to have enough for a full workday, but one set should be fine (4,500/1,400 = 3.21 hrs). I chose the XP-G to get a good balance of flood and throw and have more runtime than a similarly driven XM-L.
About the photos: I was carrying my cheap point & shoot Nikon Coolpix L20 with me which gives me limited ability to adjust settings. For instance, I couldn't adjust white balance at all. Some photos (esp. day one) have flash used in them and are therefore much much brighter than reality. I state in my captions whether the lighting in the photo was a good representation of reality. On day 2 I was experimenting with different settings and by late morning had found "Night Landscape" which disabled the flash and seemed to take photos which were more accurate to the true lighting conditions. I left the camera on the "Night Landscape" setting for the duration of the survey. All photos taken with flashlights on high mode.
I know, I know! Shut up and show us the photos! Well here you go. It's very difficult to just pick a few, so I've also provided a link at the bottom of the thread to the entire album. Captions/descriptions will be above the photo they are referring to.
First up is a screen capture of a marked up mine map with our survey points overlaid (in AutoCAD). There is a mine to the north and one to the south. This survey is in the upper/northern mine. The red lines indicate our direction of travel from survey point to survey point. Total distance travelled in and back out was 13,600 feet (2.6 miles or 4.1 km). Notice that North is rotated slightly to the left.
Next up is a photo showing the entry into the mine from inside the plant building (photo was actually taken when we came back out, but it's better than the shot going in):
This next shot is lighting up the main entry with my KD C8 (and my camera also making this brighter than it really is). Notice we have concrete floors.
Photo showing what my purpose was during this survey. I was the "backsight guy" setting up this target and tripod over a nail the "foresight guy" had established. Here we're making a 90 degree turn and heading away from the section of the mine that had concrete floors and some lighting (there is a fluorescent light just off the left side of the photo). You can see a steel roof support in the background.
Here is a view from the target in the last photo looking in the direction it was facing. Now we're headed into complete darkness!
Here is a typical setup in complete darkness. As I would look toward the direction of the instrument man I would only get glimpses of his headlamp as he aimed it my direction.
This photo is at the same location as the previous one, I just moved up and used the tripod to brace the camera on. I'm unsure of the lighting used on this photo. I'm sure it used the flash, but I'm unsure if I also used my KD C8. You can see the instrument man's headlamp ahead between two of the steel beams. (Note: These roof supports seem to have been placed long after the mine was abandoned, likely by the Mushroom plant as part of their efforts to maintain the mine and keep this entry travelable.)
On Day 2 I brought my Black & Decker Flex 360 to clamp onto the tripod to light the prism for the instrument man to see it to take his sights. Prior to this (and I still did sometimes afterward) I would stand about 10 to 20 feet in front of the target, slightly to the side, and shine a light at the target. This light proved to be one of the most versatile and most used lights I had. I would clamp it on the tripod and aim it down while I was setting up over the nail. I also used it as a general area light such as clamping it to the cap window on the back of the truck to light up the tailgate area. Battery life is so excellent that you don't have to worry about keeping it off to conserve battery. This photo is a good representation of how the B&D light on the target looked. Notice how the upper "point" of the target is shadowed by the prism itself due to the light shining up from below.
This is a different setup than above, but gives you another angle on the use of the B&D clamp light.
Ok, now for some beam comparisons! First up is my custom Mag 3C shining toward our foresight guy 800 feet away (yes 800 feet confirmed). I think that light in the foreground is actually the reflection of this light from the prism bouncing back at me.
Same setup as above, but with the KD C8 on high. It's pretty easy to see how much further the XP-G above throws over the XM-L. This is where I have said that all the bright spill from the XM-L seems to throw off your night vision for spotting far off.
Typical conditions of the instrument man's setup. He's using a Coleman Max Bubba (6AA thrower) in a clamp mount and aimed at his point on the ground (mainly for area lighting once setup). Light goes 20+ hours so it's just left on most of the time. The headlamp is his own Streamlight (it's nothing high powered, it's a Xenon/LED "dual bulb" type light). Our data collector and instrument screen both have built-in backlighting.
This is the backsight target lit the instrument man is sighting (light up by the B&D clamp light). Distance to that target is only 174 feet. This is a very realistic representation.
Same as above, but aiming the custom Mag 3C on high at the backsight. This was my intention for the use of this light underground, but I found it's not really feasible. Most of the time the light needs moved to the side so you get a better reflection (and not a blast of light back in your face, or a target so lit up that you can't make out the center).
Here's a photo of a recent roof collapse. I was taking a photo closer to it when the foreman with us said "I wouldn't stand there if I were you" and so I backed up to take this photo (with KD C8).
Our destination - the mine pool (point at which the mine becomes flooded).
Another view of the mine pool.
Some appropriate graffiti on the wall near the mine pool.
Day 3 I brought along my favorite thrower - my Dongrui All-920 (XR-E Q5 driven at about 2A). This light was fabulous for sighting long distances. The dimmer spill was enough to see around you and it didn't knock out your night vision for distant sights. This photo is lighting up the backsight target from a distance of 170 feet.
Here is a good represention of the Dongrui's throwing ability. This is about 500 feet to a wall, but it's misleading because of a hump in the floor.
First of three beam comparisons. About 500 feet to the wall (different location than previous photo) First up the Dongrui All-920. Notice the detail seen on the far wall.
Same location, with stock 2D Mag LED (latest version). Notice the very narrow beam and how much dimmer it is. It still reaches the wall.
Same location, with KD C8. Notice you can see the wall, but can't make out much detail. Defintely lights up a wider area!
Another beam comparison. This time back in a maintained area of the mushroom plant (no lighting though). First up the KD C8.
Next, the Dongrui All-920. This is a great representation of how the bright hotspot and dimmer spill work so well together. Look at the detail in the ceiling as you compare this photo with the KD C8 above.
Another beamshot comparison, similar location. First KD C8.
Now Dongrui All-920
These are just samples of the photos I came back with. My entire photo album is located within my Google Picasa site here - feel free to browse the entire album. Every photo has a caption. (Note: You won't see the entire caption until you hover your mouse over the thumbnail or view the page with the larger image.)
I had a lot of fun with this project. Both in the testing of flashlights and in being underground for the first time. Well I was underground once before in a local tourist attraction coal mine. Oh, and I went underground back in 1987 into a tourist attraction gold mine called the "Homestake Gold Mine" in South Dakota. The other guys probably thought I was nuts carrying 5 or 6 flashlights on me at a time! I wish I could have gotten a shot of the old outdated miner cap lamps our company still uses. They use a halogen bulb and are powered by a 4volt sealed lead acid battery on your belt (probably about 20 pounds). I think they run about 12 to 14 hours. I chose to use my cheap 3AAA headlamp from Walmart and was satisfied with it's performance. I left it on most of the day and got almost two full days out of it. I really wish I would have had a UF-H3 to try out! (I have one on order now.) My next task will be to try and get my co-workers decent modern headlamps. I really believe they are best suited with a very floody headlamp and a good thrower flashlight (but not too narrow of a beam), maybe even a floody flashlight as well.
Questions? Comments? (Sorry this took so long to post!)
-Garry
.) I do believe that mine pool water reaches the roof not too far back from what you can see, so you wouldn't go far back. In that first photo (the CAD drawing) you might be able to make out the blue shaded areas - that's where the water is. The water actually works it's way down into the southern mine. (Part of our company's task is to find out where the water is, where it's going, and how it's getting there.) We're proposing new mining which utilizes some of this old northern mine for access and we have to stay away from the mine pool (anyone remember the 
