Case Study · Landslide · 2013
April 10, 2013. The largest non-volcanic landslide in North American modern history occurred at a copper mine in Utah. 65 million cubic meters of rock. Two avalanches, 90 minutes apart. Speeds up to 100 mph. 16 earthquakes triggered. The debris field would cover Central Park under 66 feet. And zero deaths — because monitoring had detected slope movement five months earlier, and workers were evacuated 10.5 hours before the first collapse.
Bingham Canyon, Utah · April 10, 2013
The Kennecott Utah Copper Bingham Canyon mine is one of the largest human-made excavations on Earth — approximately 2.5 miles wide and 3,900 feet deep, visible from space. It has been operating since 1907, and large mines always have landslides: they are, as author and former Bingham Canyon geologist Dr. Brad Ross describes it, "the nature of our business." The Bingham Canyon mine had experienced significant landslides before April 10, 2013. What it had not experienced before was anything like the Manefay slide.
The geotechnical team at Bingham Canyon had been monitoring the northeastern wall of the pit throughout 2012 and into 2013 using a sophisticated network of instruments, including an interferometric radar system installed months before the event. Signs of increasing instability became evident throughout early 2013 as displacements accelerated within the unstable area. In November 2012, the monitoring systems first showed instability in the area that would eventually fail. As the instability grew through early 2013, the visitor center located within the landslide source region was closed and removed. On April 10, when movement reached approximately 2 inches per day, the mine evacuated all employees at 11:00 AM. At 2:38 PM, mine operators issued a press release warning that a landslide was "imminent and rising dust might become visible." At 9:30 PM — roughly 10.5 hours after evacuation — the first rock avalanche occurred. Over the following 90 minutes, two massive slides deposited approximately 65 million cubic meters of material in the bottom of the pit. Not one person was hurt.
April 10, 2013
Date
0
Deaths
65M m³
Material Deposited
10.5 hrs
Evac Lead Time
World's Largest
Non-volcanic (modern)
The GSA Today peer-reviewed analysis of the event, published by University of Utah scientists, documented the unprecedented scale: the two slides moved at an average of almost 70 mph and reached estimated speeds of at least 100 mph. The debris field would cover Central Park under approximately 66 feet of rubble. The slides triggered 16 small earthquakes — the first known case in which landslides had been documented to cause earthquakes rather than be caused by them. And the slide was "one of the best recorded in history" because Bingham Canyon sits within a dense regional network of seismometers and infrasound sensors that captured every aspect of the event in extraordinary scientific detail. The combination of unprecedented scale, zero casualties, and extraordinary scientific documentation makes the Bingham Canyon Manefay slide the most important positive proof in the landslide record: a functioning monitoring system, applied correctly, can provide enough warning to save every life in the slide's path — even when the slide itself is the largest of its kind.
The Science
Think of interferometric radar as a precise distance measurement taken thousands of times per day across the entire face of a slope. The system emits radar pulses and measures the time they take to return from different points on the slope surface. By comparing repeated measurements over time, the system can detect millimeter-scale movements across a wide area — movements too small to see with the naked eye but that indicate a slope is creeping toward failure. The Geoengineer.org account of the Bingham Canyon monitoring documents the progression: instability detected in February 2013, movement accelerating through spring, rate reaching approximately 5 cm per day the day before failure, then approximately 2 inches per day on April 10. That progression — accelerating creep leading to failure — is the characteristic signature of a slope moving toward collapse.
Slopes that are going to fail don't usually fail without warning — they accelerate. The movement rate of the unstable area at Bingham Canyon was measurable for months before the April 10 collapse. What the monitoring detected was not just that the slope was moving (all slopes move slightly) but that the movement was accelerating — the rate of displacement was increasing over time, a pattern that, in geotechnical engineering, is a recognized precursor to failure. The GSA Today analysis notes that "signs of increasing instability were evident throughout early 2013 as displacements accelerated within the unstable area." The Utah Geological Survey account confirms: instability first visible in November 2012, becoming more threatening in early 2013, reaching 2 inches per day by April 10. That five-month window was the warning window that saved everyone in the mine.
The Oso landslide of 2014 — the anchor event in this series — killed 43 people on a slope that had been flagged as the highest risk in the state and where warnings had been documented but never became restrictions. The Bingham Canyon Manefay slide killed no one despite being the largest landslide in North American modern history. The difference is not luck — it is monitoring technology, geotechnical expertise, and the institutional culture to act on the data when it said failure was imminent. The Mining.com.au account of Dr. Ross's assessment is precise: "First of all they knew that it was going to happen, which in itself is very different... over time the geotechnical team had gotten very good in detecting and anticipating and predicting landslides." That expertise, applied to the right instruments, produced a 10.5-hour evacuation window before the largest landslide in the modern North American record.
Timeline
01
November 2012: Geotechnical monitoring at Bingham Canyon first shows signs of instability in the northeastern wall area. The mine has an interferometric radar system and sits within a dense regional seismometer/infrasound network. Movement is small but measurable. The geotechnical team flags it for increased monitoring. The visitor center within the projected slide source region is closed and then removed from the area.
02
February–April 9, 2013: Monitoring shows instability growing, movement accelerating through early spring. By April 9, the slope is moving at ~5 cm per day. Equipment — power lines, cellular tower, and some mobile equipment — begins being relocated out of the projected impact area. Rio Tinto recognizes the progression matches failure precursors documented in prior events. April 10 morning: movement reaches ~2 inches per day. Decision: evacuate.
03
April 10, 11:00 AM: All employees evacuated from the mine — approximately 2,000 workers. April 10, 2:38 PM: Press release issued: a landslide is "imminent and rising dust might become visible." April 10, 9:30 PM: First rock avalanche. ~10.5 hours after evacuation. ~7 hours after press release. 90 minutes later: second, smaller event. Zero injuries, zero deaths. Debris covers the bottom of the pit 66 feet deep. 16 earthquakes triggered.
04
2013 onwards: Mine resumes operations despite $1B+ in damages to equipment and infrastructure (14 haul trucks, 3 shovels, main haul road destroyed). Production averages higher than pre-slide after recovery. University of Utah scientists publish peer-reviewed analysis in GSA Today — the Manefay slide becomes "one of the best recorded landslides in history." The event is widely cited in mining and geotechnical engineering as the proof case for slope monitoring.
Human Decisions
What made zero deaths possible
The interferometric radar system that detected the Manefay slope movement was installed months before the instability became visible in the data. The EarthSky account is specific: "The company that operates the mine had installed an interferometric radar system months before the event that made it possible to detect subtle changes in the stability of the pit's walls." The monitoring infrastructure that saved 2,000 lives existed because it was put in place before it was needed — a proactive investment in geotechnical surveillance rather than a reactive response to observed movement.
The Geoengineer.org account documents the critical decision: "Rio-Tinto, to its credit, apparently realized what was going to happen and had evacuated the mine at 11:00 am, about 10.5 hrs before the failure." This required organizational culture to take the monitoring data seriously enough to shut down a major production operation at a financial cost — stopping production at one of the largest copper mines in the country for an extended period — based on geotechnical sensor readings, not visible evidence of imminent failure. The decision was correct and comprehensive: 2,000 workers, equipment relocated, press release issued.
What the comparison reveals
The Oso landslide in Washington (2014, anchor case study in this series) killed 43 people on a slope that had been documented as the highest-risk slope in the state. The difference between Oso and Bingham Canyon is not the size of the event — the Manefay slide was far larger. It is the presence or absence of active monitoring and the institutional culture to act on monitoring data. At Oso, the risk was documented but not continuously monitored. At Bingham Canyon, the slope was continuously monitored and the data was acted upon. The monitoring made the difference between 43 deaths and zero.
The E&MJ recovery account of the Bingham Canyon mine's post-slide operations documents that despite approximately $1 billion in damages to equipment and infrastructure, the mine recovered and eventually produced at higher-than-pre-slide averages. The evacuation and temporary production halt were operationally and financially costly. They were also the correct decision. The geotechnical monitoring system that enabled the evacuation cost a fraction of the damages the slide caused — and zero of what the deaths would have cost in any dimension.
The cascade lesson
Bingham Canyon 2013 is the proof case for landslide early warning. The largest non-volcanic landslide in modern North American history was detected five months before it happened. The monitoring system that detected it was in place before the slope began moving. The accelerating movement data was read correctly by geotechnical engineers who had developed the expertise to recognize failure precursors. The institutional decision to evacuate — at significant operational cost — was made in time for 2,000 people to be out of the way before 65 million cubic meters of rock moved at 100 mph. The contrast with Oso 2014, La Conchita 2005, and every other landslide event in this series where the slope was known to be dangerous but monitoring wasn't in place is not a matter of scale or luck. It is a matter of instrumentation, expertise, and institutional willingness to act on data. The monitoring that saved Bingham Canyon's workers exists in more mines and on more critical slopes today than in 2013. It does not yet exist on most of the landslide-prone slopes adjacent to communities.
What You Can Do Now
Bingham Canyon proves that landslide warning works — when instruments are in place before the slope starts moving. These five actions apply that principle at the household and community level.
The USGS National Landslide Hazards Program conducts monitoring at selected high-risk sites and produces landslide hazard assessments after wildfires, major rainfall events, and earthquakes. The Bingham Canyon mine's monitoring was industry-funded, but public-sector landslide monitoring exists for many communities at risk. Find out whether your state geological survey or USGS regional office monitors slopes near your community — and whether early warning protocols exist for those slopes.
Find your local landslide monitoring resourcesAfter a wildfire, the USGS Landslide Hazards Program issues post-fire debris flow hazard assessments that function like the institutional version of the Bingham Canyon monitoring data — they assess which slopes in the burn scar pose high risk during subsequent rainfall. These assessments are publicly available and are used by emergency managers to make evacuation decisions. If such an assessment is issued for slopes above your community, treat it with the same seriousness as the Bingham Canyon geotechnical team treated their monitoring data.
Post-fire debris flow guideWhen emergency managers issue evacuation orders for landslide or debris flow risk, those orders are based on either active monitoring data (like Bingham Canyon's radar readings) or hazard assessment data (like the USGS Thomas Fire assessment before the Montecito debris flows). Bingham Canyon's team acted on their monitoring data when it reached a threshold, and nobody died. The equivalent individual action is following an evacuation order for landslide risk when it is issued — treating it as the data-based warning it is, not as a precautionary overcaution.
Landslide evacuation guideThe interferometric radar system at Bingham Canyon was installed because the mine recognized the risk and invested in monitoring infrastructure before failure. Most communities don't have equivalent monitoring on high-risk slopes above them. Advocate with your county emergency management office and state geological survey for monitoring on documented high-risk slopes near your community — particularly slopes that have failed before (like Oso) or slopes that have been flagged in hazard assessments. The monitoring that saved Bingham Canyon's workers is available technology.
Community resilience guideBingham Canyon had monitoring. Oso did not. The Oso slope was known to be dangerous but was not continuously instrumented. In most communities, "no warning has been issued" for a nearby slope reflects the absence of monitoring, not the absence of risk. The USGS and state geological surveys produce landslide hazard maps for many areas; consult them. The absence of a current warning is not a geological safety certification — it is a statement about what is being measured.
Find your local landslide hazard mapsLandslide case study series
Oso 2014 covers documented risk that never became restrictions. La Conchita 2005 covers the same slope failing twice. Montecito 2018 covers post-wildfire debris flows. Gros Ventre 1925/1927 covers landslide dam failures. Together, they document every major failure mode — and one major success — in the landslide preparedness record.
Full landslide case study seriesSources