up next on a second look, going under ground. we're going to show you the mine that is you can visit right here in the bay area and also tell you about the toxic problems some of those mines have left behind. all straight ahead on a second look. hello everyone i'm frank somerville. abandoned mines they're all over the state of california and much of the western united

states. based on historic records, they estimate there's 47,000 abandoned mines in southern california and the state knows the location of only $3,700 of them. that means that for every abandoned mine they've located there's 17 others. and it was an abandoned mine that took the life of jason adue. he was living with his wife in the basement of his mother's room when the basement gave way and he fell to his death. >> we were planning when he graduated we wanted to go to russia for two years because i always wanted to go there. i always wanted to learn russian. he was a mentor. as we spoke on the property he built a classroom to students it's called classroom clubhouse. our kids would come to our home

and he would tutor them. the home was built in an area where there had been significant gold mining in years past. and heavy rains may have led to the giant sink hole that opened up right underneath their house. the death of jason shalue also led robert handa to look at the danger of abandoned mines in the south bay. and in 2006, he visited one of those mines in san jose. >> reporter: john slenter conducts tours of the quick silver mines deep in the hills of south san jose. >> we're now traveling on mine hill road which was the original road that led up to the mining area. >> reporter: the mining operation started in the 1860 to dig for cinabar used by prospectors to separate silver and gold. slenter took me into what is left of one of the mines it was a fascinating and some what

eerie look under ground. >> we're heading toward the entrance to the san cristobal which was started back in 1866 this was used right up into 1976 they were still taking material out here. take a look at this here. hard rock mining. they had to hand drill holes into the rock and in the early days they used black powder. placed it into these holes they drilled and then set their fuses and blasted it. they're biggest problem here was not so much bad gases or bad air, but it was water. water was their biggest enemy as they blasted and dug these tunnels they encountered many under ground aquaducts and water ways. >> reporter: a collapse may have easily happened in the south bay because the last owner of this parcel had decided to divide it and sell it in small parcels.

>> if that would have happened it would have easily been that families built homes over top of them. and underneath them there would have been these tunnels. with the winter like we've just experienced the land could have been the -- the ground could have been saturated and there could have been collapses. >> reporter: the houses were never built because santa clara county steped in and bought the land to preserve the mines and buildings. now there's a museum here and tours availables saturdays through sundays. >> most of the time we get people who come off the street and they just walk in and say i've never known this was here. we've lived in the area for years and we didn't know this was here. >> reporter: the area has seen more visitors because people want to see and understand the area's past. there may be more interest in how that mining just might affect us still to this day. still to come on a second look, a ghost town with a toxic threat just outside the bay area.

and a bit later, bob mackenzie will take us inside a working land mine in the sierra foothills. [ laughter ] [ girl ] wow. you guys have it easy.

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tonight on a second look we're visiting forgotten mines. there's a mine that details the romantic legacy of the era but the toxic legacy as well. bob mackenzie first brought us this record in 2009. >> reporter: the road to this place becomes rough and rutted about 50 miles south of san jose. there are a few humans out here, there's an abundance of open land and a road that is steadily disintegrating back into the soil. as you roll through the valleys and into the hills you come to the destinations. the gold rush town of new indria. it is one of california's biggest ghost towns, the least

known and most toxic. >> there are ghosts here actually. >> reporter: cate woods has lived among those ghosts for most of the past 20 years. she and her father kent are a handful of people left in new indria which is anything but new. >> nature reclaims everything. it always will. >> reporter: kate and kemp woods have a few hundred acres and a mining claim where they prospect for what may be the rarest gem in the plant. benitowhite. named after san benito county, the cobalt blue stone is forged here in the earth's crust. it's california's official gem stone. but that's not why gold rush miners came here. dug some 80 miles of tunnels and built a town that housed miners well into the 20th

century. they built new indria around this crater. that ingredient was quick silver. mercury. >> i used to take the quick silver down in a flask by mule train. all the way down and ship it out to the railroads. >> reporter: but more than a century of mercury mining has left a toxic legacy. the abandoned mine tunnels pour rust red water infused with a heavy metal so poisonous it can cause brain damage and death. >> it's ghastly. you know it really is ghastly. >> reporter: it is not uncommon to see scientists such as these israeli scholars doing field research at new indria. >> most of this stuff was deep in the earth, when i say deep several miles down. >> reporter: gordon brown is an earth sciences professor at stanford university and has been going to new idria for threedegrees kaeudz. - - three decades. he says the quick silver is

transforming into methel spitting out of the ground water. as long as somebody doesn't drink or bathe in the water it's safe. >> i've taken my family down there several times myself. >> reporter: the water drain drains into san joaquin and into the bay but because money is tight nobody is doing anything to stop it. the contrast between the toxic ghost town and the handsome california country side that surrounds it could hardly be more stark. >> it's very dilapidated right now. it's falling down. like melting back into the ground. >> reporter: kate woods walks through the remains of new idria and hoped the city would

be reborn. >> there was a whorehouse, men dormitories, lots of mining cabins it was really a town. >> reporter: in addition to the poisons inside the interiors of some of these abandoned winters have shown signs of the contradite virus. despite it all. the history is what she likes. >> i like to show them parts of our property which actually that's where a lot of the bars and brothels were. because the matrons of this town would not allow their mining husbands to have whorehouses or bars in the town proper. >> reporter: woods who grew up in san jose and lived for a time in san francisco is undaunted by the mess. >> you couldn't blast me out of here, i mean you really couldn't. i'm not going any where. >> reporter: last year the epa added the new idria mercury

mine to its list of the nation's worse toxic sites. the federal government said it would investigate and clean up the waste at that site. when we come back here on a second look, come with us as we visit a working gold mine in california's sierra foothills. and a bit later, the rich history that lies under ground in contra costa county.

tonight on a second look we're take -- taking a look at california's forgotten mines. >> reporter: our destination is the 16 to one mine which has been producing gold for 100 years. we're visiting here because

anyone can visit this historic mine. anyone that is who is willing to pay a hefty admission fee which goes to support a mining museum. president mike miller gave us a briefing. >> these are battery-powered lights, inside here is a handle now flick it on. >> reporter: it's hot in the sierra in the summer but you dress warm to go into the mine. the temperature drops 40 taoegz as soon -- 40 degrees as soon as you walk in. what you walk in is a dripping tunnel the first that goes deep into the earth. the only light is what you're wearing in your head. if you can avoid falling in the puddles and you stop hitting yourself in the head, and you convince you're not nervous you notice your surroundings. you notice you're walking on a train track. >> there's general accidents

associated with any kind of heavy construction job. but everybody here knows it's so dangerous we take lot of steps necessary to be careful with explosives or with just communication with each other so everybody knows what the other person is doing. >> reporter: and that train that i worried about, well just as we got to an intersection here came one. >> hey, frank. >> just two more. >> the train packing a load of rocks headed down the passage we had just walked through. mike assured us nobody gets hit by trains here. a luxury elevator arrived which we were told would carry us to another tunnel 1,050 0e 1,050 -- 1,500 feet. >> we tag it all day, and at the end of the day we know who's left in the mine and for some reason if we don't come out they're going to come look

for us. >> reporter: it's been ringing a bell that operators are told where they want to go. >> three, two, three, three. here we go. >> you got it. >> sit back and enjoy the ride. now lean back. lean back like this. >> lean back, oh. >> by the way if you have any tendency toward clousterphobia this is not what you want to do on your vacation. you don't see much on this ride but what you don't see isn't encouraging. you see the light growing smaller and smaller. somehow that light seems to symbolize civilization, safety, food, water, family and friends. if you look straight ahead you see a wall of rock going past very rapidly just a few feet in front of your face. climbing out of the 1,500-foot level we encountered our next

mode of transportation. under ground rapid transit and we all get a car to ourselves. >> you may want to sit and face that way. here we go. this trip felt something like the beginning of a haunted house ride at disneyland but this is no theme park and we were cautioned to keep our hands inside the car and be ready to duck obstacles. it's probably best during this adventure not to think about the fact that there are millions of the tons of rock over your head. any way by this time we were starting to enjoy ourselves. by the way, tours of the 16 to one mine start at $95 per person. for an experience that lasts about five hours. about a quarter mile in we encountered two young miners who believed they had found some gold in an area mined many times before. >> well, you're game to give it a try. >> oh, yeah.

>> let's do it. >> our two miners, jeremiah ferrel led us to a cavern that led us straight up. it was here they said they had spotted some gold as usual embedded in solid white quartz. >> we will find out when we shoot it. >> the two men had drilled holes. into the holes john packed explosives. over the years the 16-1 has produced a million ounces of gold with luck we were about to find a few more ounces. >> fire in the hole. >> for the four minutes fused there's plenty of time to get out of the way. it was less i for one d idn'tdoddle. safely around the bend we all heard the explosions and felt them. john and jeremiah used the latest trinket in gold mining, medal detectors. >> now we're cooking. >> and sure enough they had blasted lose one large rock

that amounted to a bonanza. mike estimated it contained $10,000 in gold. >> this is what it's all about. >> wow. >> this stuff is coming back out here. >> you have to be an electrician, concrete worker, we do a lot of concrete work. >> explosives. >> yes, explosives. a mix of all trades. >> we do hard work and perseverance and things others have not done to try and find it. that's what it takes. >> as guest of honor i got the honor to climb the rock. i had a few escape plans but they didn't pan out sort to speak. when we come back, going under ground in contra costa county, we're going to take you back inside the black mine.

tonight own a second look

we're visiting california's underground legacy. the mines that lay under ground some still works, others abandoned. some leave toxins behind. >> reporter: when the district filled this valley for the reservoir, water flooded at least two mercury mines and their tailing. that mercury is now finding its way into the food chain. mercury occurred in there area very abundantly. it was leaking into walker creek. this clean up significantly reduced mercury run off into walker creek and tamales bay. but in sulahule it may be more difficult. it starts with bacteria mostly from cow dung. >> you know there's only so

much you can do with the natural resource. and it's been here for since the beginning of time. >> contaminated with mercury. there's just a warning. i mean it is posted at all entries up there. >> reporter: but today we saw no warning signs at the reservoir. it's run by the marine district. one fisherman caught a big bucket of fish. >> there's no threat to drinking that water but it is a threat to wildlife and people who are fishing in those reservoirs. >> the eastern contra costa county was once home to a massive coal mining operation. you can still visit some of those coal mines today. bob mackenzie did just that. >> reporter: go to black diamond park in antioch and take a walk into the black diamond mine. a short stretch of the old coal

mine is now open to the public. it wouldn't be going too far to say that this was the mine that built the bay area. rick yarborough gave us our tour. man who's happy undergrounds. he's verse in the history of the black diamond but could tell you what this area was like before there were mines or miners. >> it's very likely that the vegetation that was here 16 million years ago, the coal that was formed life was plant life in a tropical forest or rain forest. >> reporter: hard to believe but this mine was winds under water. we can only imagine antioch as a rain forest full of swamps. but we have a good picture of life there 140 years ago when the black diamond mines supplied the coal that powered the furnaces that ran the factories that made the san francisco bay area a new center

of industry and commerce. thousands of miners dug the hundreds of miles of tunnels that honey combed the hills in those days. it was hard grinding work, sometimes in poorly ventilated tunnels where the only light available was candlelight. young boys were handy for spaces too shallow for a man to stand up in. boys wept to -- boys went to work in the mines at 12 years old. you don't see many old coal workers because they died young, mostly because of black lung or they worked themselves to death. many gravestones have been stolen but those that remain tell of the short lives of the coal mining men >> this was part of the pittsburg line. we don't know how long it's probably the clark vain.

and the clark vain we know extends over most of the coal field. >> reporter: by the 1970s the coal boom was over. but then in the 1920s someone realized that what wasn't coal in these mines was sands. silica sands that could be made into glass. the coal opened again. the glass containers made here went around the country and were used to contain everything from booze to ketchup to black eyed peas. in 1997 we visited the black diamond when yarborough and others were still taking out sand. not to make glass but to clear the mine to open it to

travelers. the black tie -- the black diamond could be mined effectively by 12 men. men still risk their lives and their health to go down to the mines and most of them by choice. it gets in your blood they say. during that visit in 1997, mining engineer john waters tried to explain the passion. >> when you're in here working, there are no seasons, there are no night and day, the only thing that exists is what's either in the beam of your light or in the light that you have set up. >> i think a lot of people think that the mines are something from the last century that we don't use mines or need mines anymore. >> that's a very common misperception i know it's frustrating to a lot of miners. because anything that you have or use that hasn't grown out of the ground was mined out of the earth. the glasses on my face, the equipment here, the camera that your camera man is using everyone the hard hat that

you're wearing and the mic you are in your hands all of it came out of the mines. >> i'm frank somerville. we'll see you again next week.