No. The quarry is under constant supervision and complies with all industrial safety requirements. After open-pit mining ceased in 2001, the Mir Quarry was not abandoned and remains an industrial site where all safety standards are strictly adhered to.

Currently, the quarry is in a state of “wet conservation”, an internationally recognized practice for maintaining such sites in a stable and safe condition.

The quarry undergoes comprehensive monitoring, including:

• Hydrogeological monitoring: regular measurements of water levels in the quarry and mine shafts, chemical analysis of groundwater, and forecasting of trends in their changes.
• Geotechnical monitoring: observations of reference points to detect shifts and deformations in the quarry zone.
• Geomechanical monitoring: instrumental and surveying observations of slope movements.
• Permafrost monitoring: temperature control of permafrost layers.
• Environmental monitoring: air quality control, hydrogen sulfide concentration, pollutant levels, and acoustic impact.
• Geodetic monitoring of buildings and structures in the surrounding area.
• Commission inspections: periodic visual assessments based on established criteria.

The quarry’s observation system includes:

• 5 observation lines on different slopes.
• Over 50 reference posts around the quarry.
• 5 posts for measuring hydrogen sulfide concentration.
• 2 posts for noise level monitoring.

Slope condition assessments are based on complex engineering parameters, such as:

• Relative and absolute horizontal and vertical deformations of the rock mass.
• Deformation rates.
• Stability safety factor.
• Presence of cracks.

Over 25 years of continuous monitoring, no cracks indicating potential collapse have been detected. In 2025, the Mir Quarry’s condition is rated as “Reliable” according to the standards of the “Mir Mine Conservation” project documentation, approved by the Central Commission of Rosnedra.

Monitoring is conducted by both independent state laboratories and specialized ALROSA services. Control results are regularly published and comply with safety standards.

In particular, state monitoring of natural water quality in nearby rivers is carried out by an independent laboratory of the Republic’s Ministry of Ecology, with results regularly published on the official website. As of today, all monitored parameters meet established standards.

The Mir Quarry is in a state of “wet conservation”. In 2025, the mine’s conservation period was extended until January 1, 2047. The updated project received approval from the Ministry of Natural Resources and Ecology and a positive conclusion from the project documentation expertise.

The Mir Quarry’s condition in 2025 is assessed as “Reliable”.

No. The city of Mirny is situated significantly higher, on permafrost over 300 meters thick, which is impermeable to water. Calculations indicate that the water level in the quarry will stabilize at approximately +220 meters above sea level, while the city is located at +335 meters. Physics simply will not allow the water to rise higher.

The Metegero-Ichersky aquifer is a pressurized system located deep underground under the pressure of rock layers. Water enters the quarry from below, and its level rises further in spring and autumn due to atmospheric precipitation. Rain and snow dilute the upper layers of the water body.

The rate of quarry filling decreases each year. According to calculations, by 2089, the water level will reach +220 meters. This is the maximum: at this level, the pressure in the quarry basin and the underground aquifer will balance out. The laws of physics will halt further water level rise. If the water volume in the basin exceeds this equilibrium, the excess will flow back into the aquifer until pressure stabilizes.

The quarry is “aging”: time, wind, and water have smoothed out sharp slopes, turning them into gentle inclines. “Wet conservation” helps such industrial sites remain stable and safe. The slow filling of the basin with water plays a key role: it protects the slopes from weathering and creates additional pressure on them, stabilizing them. The only visible changes are minor landslides in the upper parts of the slopes, which are superficial and not associated with collapse risks.

To verify slope stability, experts conducted complex mathematical modeling. It showed two scenarios: leaving the quarry dry or filling it with water. In the first case, without water protection, winds and precipitation accelerate weathering, causing slopes to gradually erode. However, even in this scenario, sudden collapse would not occur. The stability safety factor (SSF) in a dry state is 1.202, above the minimum acceptable level of 1.2.

In the second scenario, with the quarry filled with water as is currently the case, stability is significantly higher. Filling the quarry creates a natural hydraulic “shield”: water presses on the lower slope tiers, preventing their movement. The SSF in this case reaches 1.759, 45% above the baseline.

Another interesting consequence of halting operations is that the roads once used by heavy BELAZ trucks and steep ledges have smoothed out over time, turning into gentle terraces. At the bottom of the basin, a natural buttress has formed — a supportive landform similar to those engineers use to reinforce slopes on highways and railways. This natural “barrier” further secures the slopes and enhances their stability.

No additional slope reinforcement is required. Since 2025, the Mir Quarry has officially been in a state of “wet conservation”, a globally accepted practice that keeps such industrial sites stable and safe for decades. The conservation project’s technical solutions have been approved by the Sakha (Yakutia) Republic’s Ministry of Ecology.

Filling the basin with water is a key element of this strategy. Water not only protects the slopes from weathering but also creates the necessary hydraulic pressure to stabilize them, eliminating risks of collapse or brine leakage to the surface or rivers.

The filling dynamics align with calculations: today, the water level in the quarry has reached +95 meters, and the inflow rate is gradually decreasing. Forecasts indicate that equilibrium between the underground aquifer’s pressure and the water volume in the quarry basin will be reached by 2089, when the water level rises to +220 meters. For comparison, the city of Mirny is at +335 meters, over 100 meters higher.

The “Mir-Deep” mine will be built far beyond the Mir Quarry’s boundaries, outside the hazardous zones of the flooded diamond deposit workings. In other words, the construction of the “Mir-Deep” mine does not affect the flooded areas of the Mir Quarry.

Under the technical project for the Mir Mine’s conservation until January 1, 2047, a “wet” conservation method has been adopted for the quarry. This is a globally accepted practice for maintaining such industrial sites in a stable and safe condition. Natural filling of the quarry with water is essential: it protects the slopes from weathering and collapse, preventing oxygen penetration and creating necessary pressure on the walls. Slope collapse, which could pose risks to people, the city, or the environment, does not occur.

Special mathematical modeling was conducted to assess slope stability, forecasting outcomes for two scenarios: a dry quarry and one filled with water. The stability safety factor (SSF) must be at least 1.2. Currently, the SSF for open slopes is 1.202, meeting the standard. When the quarry is filled with water, the SSF increases to 1.759, over 45% above the required value. Water in the basin adds pressure to the lower slope sections, preventing collapse.

An example of “wet conservation” is the world’s first diamond quarry, the “Big Hole” in Kimberley, South Africa. This quarry, 463 meters wide and 240 meters deep, was flooded after mining ended in 1914. Located in the city center, it has remained stable for over 110 years and is now part of a museum complex.

The brines filling the Mir Quarry are not a “chemical cocktail”, as sometimes portrayed, but natural groundwater from the Metegero-Ichersky aquifer. They are indeed salty, with a mineralization of about 100 g per liter (for comparison, the Dead Sea has about 300 g per liter). However, these waters are deep underground, within the quarry’s confined space, and do not interact with surface layers or ecosystems.

There is no danger to the city’s residents or the environment. The water mass and mineralization levels are monitored by an independent laboratory of the Sakha (Yakutia) Republic’s Ministry of Ecology.

No, such risks are ruled out.

The city of Mirny is located at +335 meters above sea level. Nearby water bodies, such as streams and the Irelyakh River, are fed solely by atmospheric precipitation: rain and snowmelt. These watercourses in Yakutia are shallow, only a few meters deep, with a permafrost layer over 300 meters thick below, which is impermeable to water, preventing it from moving upward or downward.

The Mir Quarry extends 525 meters deep. At its base lies the Metegero-Ichersky aquifer, a natural underground reservoir of mineralized water, or brines. This aquifer, located beneath the permafrost layer, spans from Irkutsk Oblast to the Laptev Sea and is about 170 meters thick.

The aquifer is pressurized, so water flows upward. In spring and autumn, the quarry’s water level also rises due to precipitation. The incoming water mixes with rainwater and snowmelt, making the upper layer less mineralized.

The rate of quarry filling decreases yearly. According to calculations and observations, by 2089, the water level will reach +220 meters, the maximum point at which the underground aquifer’s pressure and the water column in the quarry will balance, halting further rise. Over 115 meters will remain to the surface.

Brines cannot leak out: the quarry’s walls and surrounding rocks consist of permafrost, which reliably isolates groundwater from the surface. There is no hydraulic connection between the groundwater and rivers, so brines cannot enter natural water bodies or cause an environmental threat.

In the groundwater of the Metegero-Ichersky aquifer, hydrogen sulfide is present in dissolved form. Its molecules are bound to other elements, ruling out the possibility of a dangerous gas bubble forming. Hydrogen sulfide can only be released into the atmosphere when the upper water layer with a high concentration comes into contact with air.

In micro-doses, hydrogen sulfide periodically surfaces as small bubbles with an unpleasant odor. Previously, Mirny residents noticed this smell, but in recent years, it has disappeared due to the dilution of the quarry’s upper layers by precipitation and a decrease in hydrogen sulfide concentration.

ALROSA conducts quarterly air monitoring at five posts around the quarry. Over the past four years, no exceedances of permissible pollutant concentrations in the air have been recorded.