Fall 2005 Will the Berkeley Pit Overflow? One of the most often asked questions from PITWATCH readers is whether the Berkeley Pit will ever overflow. The answer is NO, and the Committee wanted to reprint information from previous editions about this question. First, federal orders are in place that established the maximum level that the water will be allowed to reach - 5,410' above sea level. Failure to keep the water below this Critical Water Level would result in steep fines (up to $7,500 per day) for BP/Atlantic Richfield and Montana Resources. It is also important to note that the rim of the Berkeley, even at its lowest point, is at 5,509' - almost 100 feet above that critical water level. Second, there are 20 separate bedrock wells and shafts, located throughout the East Camp underground system, to monitor water levels. If the water level approaches 5,410' AT ANY OF 14 SELECTED COMPLIANCE LOCATIONS, water pumping at the Berkeley must begin. We also know that the recorded levels at several monitoring sites are as much as 20' higher than the water level in the Pit, so the pumping will actually have to start that much sooner (see graphic about the Anselmo by clicking here). Third, if for some unforeseen reason the water level in the Berkeley Pit were allowed to rise unchecked, the water would still never overtop the rim of the Pit. At some point, groundwater flow would eventually reverse direction. Instead of flowing toward the Pit, as it does now, the water would begin to flow away from the Pit, into the void spaces between the sand grains in the alluvial aquifer. This underground water movement would prevent the Pit surface water from ever approaching the rim. But, remember, given the federal orders, potential fines, and all the monitoring going on, the water will NOT be allowed to rise unchecked. Another thing to remember is that no matter when its time to start pumping and treating, the Horseshoe Bend Water Treatment Plant is already in-place and operational, complete with a discharge line from the plant to Silver Bow Creek. Likewise, because Montana Resources 'mines' copper from Berkeley Pit water, a pumping system and pipeline are also in place to transport water from the Pit to the plant. Improvements planned soon at Berkeley Pit viewing stand PitWatch Issue Volume 10, Number 2 The Berkeley Pit Viewing Stand has long been a popular spot for tourists and residents in their tours around the Mining City. Now, thanks to a generous contribution from the Washington Corporation, plans are moving forward to create a grand new appearance on Continental Drive. The Butte Chamber of Commerce, which has recently taken ownership of the site, has unveiled an ambitious building program that includes an interpretive pavilion, restrooms, picnic tables, benches, playground and park. Improved parking areas, site lighting and a full array of landscaping enhancements are also planned to transform the site into a first-class attraction. The project budget is almost $300,000 and the target date for completion is June 1, 2006. Fund raising is at full throttle. Besides their $100,000 contribution, the Washington Corp. has pledged another $75,000 as a dollar-for-dollar challenge grant to solicit matching funds. The Chamber has committed the money collected from charging a $1 entry fee to the viewing stand, which generated almost $20,000 in 2005. Butte-Silver Bow will apply for a state grant to help with landscaping and the irrigation system. The project is designed to make an outstanding first impression on visitors to encourage them to explore and learn more about Butte's rich mining heritage. The Viewing Stand improvements are also part of a larger effort to reclaim the Continental Drive corridor as a gateway to Historic Uptown Butte. Earthquakes did not affect Pit A 5.6 magnitude earthquake centered near Dillon on July 25, 2005 did not affect the Berkeley Pit. There was no Pit wall sloughing or change in the water levels in the Berkeley Pit, the underground mine shafts, the alluvial aquifer wells, or the majority of the bedrock monitoring wells. However, two bedrock monitoring wells (A&B) showed changes. Well A showed an initial water level decline of about one (1) foot after the earthquake, and the level stayed lower for a number of days before rising again. Well B, which is located in an area that wasn't dewatered as extensively by historic mining activities as other portions of the bedrock aquifer had a 9-foot drop in water levels in the month following the earthquake. Recently, the water elevation in Well B is rising again. One possible explanation for the lower water level in these wells is that the earthquake opened up existing fractures in the bedrock surrounding the wells. Water then flowed into these fractures until the bedrock adjacent to them became saturated. When that happened, the water levels began to rise again. Since the July earthquake, there have been two additional quakes in the region, one of which was centered in the Butte Basin. Both of these other quakes were considerably smaller in magnitude, and no effects were noted in the Berkeley Pit or bedrock monitoring wells. Spring 2005 Can the Pit Withstand an Earthquake? PitWatch Issue Volume 10, Number 1 Tsunamis, volcanoes and earthquakes in recent months have created an increased interest in seismic activity. Many readers have written, called, or stopped by questioning what will happen to the Berkeley Pit if an earthquake occurs in Butte. To help answer these questions, local experts were asked to explain the likelihood of an earthquake and what effect it would have on the Berkeley Pit. Probability of an Earthquake in Butte This aerial photo taken in 2001 shows the location of the Continental fault east of Butte. It has been monitored closely for 25 years and has not shown enough activity to prompt earthquake concerns. Mike Stickney, Director of the Earthquake Studies Office at the Montana Bureau of Mines and Geology says that Butte is not likely to suffer a severe earthquake anytime soon. Large earthquakes are certainly possible in western Montana as demonstrated by the 1959 Hebgen Lake earthquake (magnitude 7.3), but are most likely to occur in the more seismically active regions located to the north, east, or southeast of Butte. The state of Montana is unlikely to experience earthquakes larger than the 1959 earthquake because the faults are not large enough to produce earthquakes greater than magnitude 7.5. Stickney also explained that Butte has been monitored closely for seismic activity over the past 25 years. There has never been any significant seismic activity recorded that suggests the nearby faults to be active enough to cause a large earthquake. Most seismic activity that registers in the Butte area is caused by blasting at the open mine site, and very minor underground subsidence, especially near the old block caving zones under the Kelley Mine. Effects of an Earthquake Even assuming a worst-case earthquake scenario, the Berkeley Pit would not overflow. Experts suggest that there would be far more damage to buildings and other structures in Uptown Butte than would be caused by adverse impacts from the waters in the Berkeley Pit. Studies show that the Yankee Doodle Tailings Pond Dam would withstand at least a 6.5 magnitude quake. It can also be assumed from similar studies that such a quake could cause some sloughing on the pit walls, but the resulting movements would not discharge enough rock and materials to cause the water in the pit to overflow. Sloughing and Landslides Although earthquakes are not likely to be a problem, landslides and sloughing of the Pit could occur. The majority of the Berkeley Pit walls are made of "solid" bedrock. However, the southeast wall is composed of "loose"silts, sands and gravels, and this is the area where sloughing is most likely to occur, with or without a major earthquake. In September 1998, about 1.3 million cubic yards of "loose" alluvium on the southeast wall sloughed into the Pit. This event caused a 3-foot rise in the water level and surface waves greater than 20 feet. The water rise associated with any pit wall sloughing would ultimately depend on the volume of material that breaks free and displaces the water. But it should be noted there is enough space for more significant events. For example, there is more than 150 feet between the current Pit water level (5,252' above sea level) and the Critical Water Level (5,410'), and there is another 100' feet up to the rim of the Pit. Summary If an earthquake were to occur, the effects of seismic activity at the Berkeley Pit would be the least of Butte's worries. Since a large earthquake is not likely anytime soon, and because landslides are relatively manageable, the public should not be overly concerned. There will probably continue to be some sloughing on the benches and old roads, but not enough to cause the Pit water to rise more than a few feet. Meet the 2005 Science Fair Award Winners Each year the Berkeley Pit Public Education Committee awards $50 savings bonds to grade-school students and a $250 savings bond to one high school student who compete in the Montana Tech Science and Engineering Fair. To qualify for the awards, the science fair project must explore a topic related to the Berkeley Pit or a mine waste cleanup technology. Sam Kuglitsch 5th grade, Kennedy Elementary "Plant Growth Effects from Environmental Factors" Randi Phelps 7th grade, East Middle School "Is There a New Antibiotic in the Pit?" John Metesh 8th grade, East Middle School, Butte "To leave or not to leave; what difference will it make if we remove the (Parrot) tailings?"