Earl Bennett is the retired Dean of the College of Mines at the University of Idaho and is the former Director of the Idaho Geological Survey.

Q: What’s your take on Silver Valley in 2005?

A: I think this is going to be the next Sun Valley in Idaho. If you had been here twenty years ago, and driven through this area, and taken a look when the old smelter was here and the zinc plant and all the mining and the tailings were all in the valley, and the vegetation hadn’t been re-established on the hillside, it looked considerably different than it does today.

And if you look at the historical pictures from back in the 1920’s and 1930’s when the smelter was running with a short stack and the valley would be full of the smoke from the smelter, and all of the area was full of tailings, and the south fork was running milk-white with the tailings it was carrying, you wouldn’t have even been able to believe that it’s the same place that it is today.

So, for folks who are here for their first time, I think it’s getting to the point now where they kind of wonder, 'what’s all the fuss been about? It looks pretty good to us.' And it does. It‘s coming back remarkably well.

Q: The lead smelter in the valley was the chief source of lead poisoning. Explain how the lead smelter worked.

A: When it was built in 1917, it essentially had one purpose. It takes the ore when it comes out of the ground -- and the ore in the Coeur d’Alene district is three primary minerals called tetrahedrite, galena and sphalerite. Sphalerite is the zinc ore. It’s a combination of zinc and sulfur. Galena is the lead ore, a combination of lead and sulphur. Tetrahedrite is a copper anemone sulphite which also has a significant amount of silver in it in the area.

Those are our three primary ore metals. To get the metals out of the ore, you essentially have to melt it. This process has been around for thousands of years; and the early Bunker Hill smelter used almost the same metallurgical technique on a larger scale than had been used by the ancient Greeks and Romans.

What you essentially do is take those three minerals and melt them. When you melt them, the sulfur combines with oxygen and comes off as sulfur dioxide; and sulphur dioxide,early on and throughout all the period up until we started to produce sulfuric acid to solve that problem, was always an environemtal liability. My understanding is sulfur dioxide doesn’t actually kill off the vegetation but once the vegetation is gone, new vegetation can’t reestablish itself because the soil becomes highly acidic. That all changed because the problem with S02 was solved when we started to produce sulphuric acid.

The emissions that come off of this plant as you are melting the ore go through two things: the sulphur dioxide as I’ve explained is captured as sulfuric acid. The particulates that also come off of the process go through a filtration system which is generally referred to as the “bag house.” In the days of the Bunker Hill smelter, especially in the 1970’s, the bag house consisted of a series of big sausage- shaped filters. They looked very similar to the big vacuum systems that you see that vacuum out your air conditioning and heating ducts. They were made out of Pendleton wool, and they filtered out the particulates.

One of the particulates they filtered out was lead oxide. I’ve spent some time dwelling on this because it’s important to realize, lead oxide is a much more biologically available source of lead than lead sulphite. So when we talk about lead poisoning in the Coeur D’Alene, the miners did not suffer from lead poisoning because they were dealing with galena, the lead sulfite. The folks who had the problem with lead were the ones who were working in the smelter that dealt with lead oxide. The other name for it is litharge.

Q: You talk about the sins of our fathers. What happened in 1973?

A: In 1973 our fathers did a real sin. It was illegal what they did in 1973. It’s illegal now; and I don’t think there’s anybody mining related or not that would try to justify what they did.

There was a fire in this bag house that filters out this litharge; and because metal prices were very high at the time, Gulf Resources management made the decision to go ahead and continue running the smelter, even though, with a part of the bag house gone, they knew there was going to be a tremendous increase in emissions of litharge, or lead oxide, out of the stacks.

And that, unfortunately, is exactly what happened. I believe it was August of 1973 that the fire occurred; and they ran the smelter almost a year before the bag house was completely repaired. It’s estimated that there was something on the order of 40 to 60 tons of lead oxide per month that was dumped out into this area, which was a huge increase of what it would have been with a filtration system in place.

Q: What was the effect on the children?

A: Just after the bag house fire, and nobody knew about this until some law suits were done a few years later, but just after the bag house fire in 1974, Panhandle Health decided to start doing some blood lead level testing of children in this area. The children that they tested near Smelterville, almost 100% of them had blood lead levels that were some of the highest that had been recorded in recent history in this country.

They were 40-plus micrograms per deciliter, when today what we’re striving for is 10 micrograms per deciliter and what the health experts would really like to do is get you down to zero micrograms per deciliter. This was the wake up call.

I believe there was around a thousand children tested overall in the valley. Now the rest of them, close to 50%, had very, very high blood lead levels, and that got people stirred up to start looking into what was going to happen.

The first law suit that was brought was by a family named Yost, and they ended up winning. They got a significant settlement. And during that trial is when the corporate records about the bag house fire came out. And again, it was a conscious corporate decision that was made to go ahead and do this. This was not like we are going to have S02 emissions come out because we have no way to get rid of the S02 emissions like in the old days. So it was a very significant legal event within the district, and probably the worst thing that I’m aware of that companies consciously did that had an impact on the health and the environment within the valley.

Q: So it sounds like Gulf Resources really was the “bad guy” in this valley.

A: Gulf, I think, was definitely the bad guy, as far as the bag house fire goes. Gulf was a little tiny company compared to Bunker Hill when they took them over; and it surprised a lot of people when it happened.

One of the goals I think Gulf had was to try to increase the productivity of their plants; and they did put a lot of money into it. They put $11,000,000 into building the tall stacks, which was supposed to help with some of the emissions problems. They put a new centering machine in at the smelter. I believe that was done by Gulf. They did try to improve the technology and also the productivity of the properties they had. So I think from a business sense they weren’t all bad; but I don’t think, certainly, most people in the valley would say it was the same company as when the old Bunker Hill Company ran it. It might not have been quite as efficient back when Bunker Hill was running it; but Bunker Hill was, at least from WWII up until 1968 when Gulf bought them out, a pretty community-friendly company to work for.

Q: What did the recent national report say about lead levels in children?

A: The good news is, in the last testing, almost every kid in the valley they have tested is down below 10 micrograms per deciliter. The criticism, if it is a criticism, that came out in the National Research Council’s Report that was done on EPA’s involvement in the district, is that the critical age for kids is 1 to 4 years of age, mainly because that’s when they are eating everything.

They are stuffing yard dirt, grass, everything else [in their mouths]; and it is also a major period of brain development, and those are the years of concern for leading. You don’t want to be leaded at any age, but that’s certainly the major concern.

So the National Research Council suggested that Panhandle Health and the other people put more emphasis just on that 1-4 age group, whereas now I believe the results are presented for a broader spectrum of age ranges – one to ten or one to nine, somewhere in there. I didn’t see that as a criticism; I saw it as almost an affirmation that the blood lead level testing program has been successful and needs to even be more improved than it was in the past. So that was quite interesting to me.

Q: How bad was the air pollution when the mines and smelter were operating?

A: I understand the valley was pretty grim. This is a valley. You do get temperature inversions in here which tend to hold the smoke in. We’ve got some pictures from Osburn that were taken in the 1930’s that we use primarily to show the extent of the tailings that used to be near Osburn prior to WWII, when they re-mined most of them. But in the background there is this kind of gray haze, and originally I thought it was just bad pictures from the 1930’s, and I showed it to some of the people up here, and they look at it and say, 'Oh, no, no. That looks like what it used to look like when the smelter was running.' So you would get smoke literally every where.

It was not that there were not solutions for their time, but, again, this is the sins of the father type thing that you have to keep in mind. When they built the smelter in 1917, they did some studies as best as they could, meteorology studies in those days to determine where wind currents were going to go, when they were going to have inversions. They knew all these things happened, of course. And they knew where the smelter plume was going to go.

And what they did was, they went to the folks who were going to be really impacted by that plume and bought smoke easements on their property. They bought the right to essentially pollute the ground with the smoke. And they did the same thing as far as tailings go down in the Chain Lakes.

When the farmers began to sue the mining companies at the turn of the century over pollution of the land down there, of their farm land by mill tailings, what the mining companies did was they bought pollution easements on that farm ground. And today if you buy land down there, the old deed, when you look at the deed, it’s got clearly in there that the Miner Owners Associations had purchased the rights at such and such for tailings disposal.

Would we accept that today? Of course not, but that’s the way it was done 40-50 years ago.

Q: What dangers do tourists face today in the Silver Valley?

A: None. In my opinion, none. It’s one thing to be exposed to that type of environment day in and day out for years and years and years. It’s another thing just to come zipping on through and take a look and go on. If you look at what the valley looks like today compared to what it did in the 1920’s or 30’s, you wouldn’t even recognize it was the same place.

I think there is no problem with tourism. The only problem I have with tourism is they haven’t marked these sites, and the reclamation has been done so well that a lot of the mining history is disappearing. At one time I wanted to put little concrete monuments up with numbers on them pointing out where these sites were. A whole lot of the direct history on the ground of this district will be lost, and I think that is sad because I think the history of this district is absolutely fascinating. It’s part of our nation’s history from the labor end, from the mining end. It’s a key element in Idaho’s history, and I wish we would do a little better job commemorating where all these most interesting stories actually happened.

Q: Will mining ever come back to this area?

A: I’m like all the other geologists that have worked in this area. We all think there’s much more there than has been mined so far. So from that end, we think the silver elephant still sits in these hills out here. Now, whether it will ever be mined or not, I don’t know, and that gets into the whole end of the economics of silver and base metals, the lead and zinc. Bunker Hill Mine still has a substantial resource of zinc in it. Whether that will ever be mined or not I have no idea.

The mining is not an issue any more. You can’t do mining today without all the environmental safe guards in place. If you were to set out to design a new mine with modern technology applied to it, you'd have to build in the environmental safeguards to implement the plan. It’s all part of one big package. So, could we go in and open up the Sunshine Mine? Oh, you bet, I think we could; and I think we could have 300 mining jobs working up at the Sunshine Mine, pulling out fabulously rich silver ore and still have hundreds and hundreds of people enjoying skiing and snowmobiling and everything else in the area, and the two of them would be compatible.

Q: So you’re fairly optimistic about this valley?

A: Oh, I’m very optimistic about this valley. One way or another, it’s a winner, whether it’s from the mining end or the tourism end.

Look at the bike trail, now the number one bicycle trail in the United States and growing in popularity every day. There’s a great example of how the sins of our fathers have turned out to be a great asset to a lot of people – not all people – but to a lot of people who now can come to Idaho, bicycle 70 miles or whatever it is over the old swinging bridge and through all this incredible country. It’s a wonderful asset and it’s just another part of what will continue to be the fabulous Coeur d’Alene mining district.

Q: What about the acid water flowing out of Bunker Hill mine?

A: One of the major environmental issues you have in a lot of mining sites is called acid mine waste drainage. Water that percolates down through mines that have sulfite minerals in them become acidic, very acidic. The Ph I believe of the water coming out of the Bunker Hill Mine is about 2.0, very, very, acidic. It used to be, if you left a shovel sitting in a ditch and you came back a week later, there was a wooden handle sitting there in the water and the iron part of the shovel would have been dissolved away. Those are some of the stories we used to hear. It’s pretty acidic.

Gulf Resources built a water treatment plant to solve the acidic problem and that plant is till operating today. And unless we find a new technology to solve the issue of acid water out of the Bunker Hill Mine, that plant will operate in perpetuity, forever.

Under the Superfund funding system, Idaho has to pick up 10% of the cost of the mitigation in this area and will have to pick up -- I think it’s a million dollars a year cost to run the water treatment plant at Bunker Hill -- and that will have to be run in perpetuity.

There is research underway as to other ways we may be able to seal off that part of the mine from surface waters to keep the water from running through the main part of the mine where we’re generating all this acid. Most of the mine does not have that problem.

A good thing about the Coeur D’Alene district is the Bunker Hill mine is, I think, the only mine that has a serious acid problem. In most of the other mines, because they were relatively narrow veins, there was not a lot of surface exposure of the mines. You don’t generate any acid water out of them. So acid mine waste drainage is not a huge issue anywhere else in the district that I’m aware of, except at the Bunker Hill, and that’s the one that always gets the main play.

Q: What about the problem of zinc in the water?

A: Well, again the NRC Report takes EPA somewhat to task for not having as good a handle on where zinc comes from, for example. And zinc right now is, in water, the main metal of concern, not lead. Lead is still important but it’s not the main concern. Zinc is.

The Idaho Department of Environmental Quality has done a lot of work in locating the source of zinc loadings in the waterways in the area here, and, I thought, had a pretty good handle on it. We know where the zinc is getting into the South Fork of the Coeur d'Alene River from in this area. There was a significant amount that used to be loaded out of Pine Creek. They’ve done a lot of mitigation in Pine Creek. I believe that has been greatly reduced but we still have out of Canyon Creek a significant zinc loading from all the big mines that were up there.

Knowing where it’s coming from and getting zinc out of the water are two entirely different issues. You can sample and find out where it’s coming from. How you get it out of the water is a much, much more difficult problem, especially if it is in an active waterway. If you’re going to do something like a water treatment plant at Bunker Hill, that’s a lot of acid water, but at a relatively low volume, compared to trying to treat the water that is coming out of Canyon Creek or something.

It’s a very difficult problem and again, one that may have to run forever. There have been, for example, tests done where you can build a wetlands, and the organics within the wetland will get a lot of the zinc out of the water. Lots of those kinds of natural possibilities.

Q: Should Coeur d’Alene be worried about zinc in the water?

A: Zinc is a problem for fish but again, for everybody who can give you a negative story, there’s somebody else who gives you a positive story. The only metal in normal water times that I’m aware of that is higher than background in Lake Coeur d’Alene is zinc. And I also understand that you’d have to drink about 7 to 8 gallons of Coeur d’Alene water to get the same amount of zinc that is in a Centrum mineral or vitamin capsule with mineral supplements. So it’s not a problem. Unless you are as bad a swimmer as I am, you’re probably not going to suck down 7 or 8 gallons of water in our beautiful lake.

We want to maintain a relatively high oxygen content in that lake; and the normal trend for lakes as they age is to become anoxic, which means they lose their oxygen content. For the tailings that are in the bottom of the lake, there’s a lot of discussion about what could make those metals more mobile; and as far as I know, nobody is quite sure.

If we can keep the water quality the way it is right now, there is less chance of those metals becoming mobile out of the bottom of the lake, which is where we want them to stay right now, in the bottom of the lake.

Now one of the problems you have with that is algae blooms. Because Lake Coeur d’Alene is a glacially dammed lake and it’s not very deep for its size, in warm weather you tend to get rather large infestations of algae blooms. Algae blooms eat up all the oxygen in the water, make the water essentially anoxic, and could be a problem for you, especially in the shallower ends of the lake, for metal release in the bottom.

Guess what kills algae? Zinc. So maybe having a relatively high zinc content in Lake Coeur d’Alene is not bad as far as having some controls on these algae blooms. So as I said, for every negative story you hear someone on the other side can come in with a positive story.