The dust emission from tailings ponds and other industrial sites in the Kryvyi Rih Iron Ore Basin is a long-standing issue. Despite industrialists’ assurances of “successful dust suppression measures,” I have collected sufficient evidence to the contrary. Using modern data analysis methods and satellite imagery results, it can be confidently stated that the dust suppression technologies currently used by the Kryvyi Rih industry are utterly inadequate for environmental protection. The multi-kilometre dust trails from the Kryvyi Rih tailings ponds vividly demonstrate the significant negative impact of the Kryvyi Rih mining and metallurgical complex not only on the city of Kryvyi Rih but also on the entire surrounding region. When settling on the ground, huge volumes of dust blown by winds from Kryvyi Rih’s industrial sites impoverish the fertile soil layer. Considering the long-term nature of these processes, it is possible to predict a gradual decrease in the quality of agricultural lands due to the constant introduction of quartz and other mineral dust. Quartz, the main mineral in the dust from tailings ponds, causes a high silicon dioxide content, significantly increasing the risk of pneumoconiosis and dust bronchitis in the surrounding areas.
The title of this article is a rephrased quote from the science fiction novella “Roadside Picnic” by Boris and Arkady Strugatsky: “HAPPINESS FOR EVERYBODY, FREE OF CHARGE, AND MAY NO ONE BE LEFT BEHIND!” (English translation by Antonina W. Bouis, 1977). The industrial landscapes of the Kryvyi Rih Iron Ore Basin fully correspond to the sceneries described in the novella. Among all other objects, tailings ponds and huge dust-water reservoirs towering over the surrounding area stand out with particular contrast. The tailings ponds are the primary focus of this research, although the findings can confidently be extrapolated to other industrial sites of Kryvbas: waste heaps, product storage areas, slag dumps, etc.
The main dust suppression measures consist of either complete flooding with water or constant irrigation of the above-water parts of the tailings ponds. Various additives are used to consolidate the surface layer, including a bischofite solution. However, using additional binding agents significantly increases the cost of the dust suppression technology.
It should also be noted that dust blowing is observed not only on the working surfaces of the tailings ponds. These facilities produce dust “as a whole” – technological roads, slopes, and embankments. Even with the working surface of the tailings pond flooded or fully irrigated, a large amount of free dust accumulates in the embankment parts and on the slopes of the facility. Under favourable meteorological conditions, extreme dust blowing begins. In this case, the dust blowing occurs not on the working surface and main roads of the tailings pond (to which all dust suppression measures are directed) but on the entire facility.
The starting point of this research was recording extreme dust-blowing incidents in tailings ponds in April 2018 using satellite imagery data from Sentinel-2A and Sentinel-2B. The results of the satellite imagery on April 20 and 22, 2018, show multi-kilometre dust trails blown from the tailings ponds of Kryvyi Rih’s mining and processing enterprises. The maximum length of the dust trail recorded on these days is more than 20 km – a trail from the tailings pond of the Ingulets Mining and Processing Plant. The highest visible density of the airborne dust flow on these days was recorded from the tailings pond of the Central Mining and Processing Plant. Both “records” were captured on April 20, 2018, by the Sentinel-2B satellite. However, other tailings ponds in Kryvbas also spread dust to the surrounding areas on these days. These facts were also recorded by satellite imagery.
The actual recording of extreme dust blowing based on satellite imagery provided grounds for a detailed study of the meteorological conditions observed on these days. Data from previous years were examined after identifying the extreme meteorological conditions under which tailings ponds’ dusting incidents occur. Going “back in time” and selectively checking satellite imagery data from past years indicates that extreme dust blowing from Kryvyi Rih’s tailings ponds is a long-term systemic problem. Moreover, this problem has remained unsolved for at least the last 13 years (since 2006 – the “oldest” point of our research). I am confident that satellite imagery from the 1980s and 1990s would also show multi-kilometer dust trails from Kryvyi Rih’s tailings ponds.
To determine the meteorological conditions that contribute to extreme dust blowing from Kryvyi Rih’s tailings ponds, data from the Aviation Meteorological Station of the 2nd category “Kryvyi Rih” (Lozuvatka village, Kryvyi Rih district, Dnipropetrovsk region) were involved. Two meteorological parameters were examined – wind speed and relative humidity of the atmospheric air. Comparing the temporal course of these two parameters with the time intervals of satellite imagery provides a clear recorded fact: extreme dust blowing from Kryvyi Rih’s tailings ponds occurs at a wind speed of 7 m/s or more and, at the same time, at a relative humidity of 60% or less.
In addition to comparing meteorological conditions during the flights of Sentinel-2B (April 20, 2018) and Sentinel-2A (April 22, 2018) satellites, the above diagram clearly shows the daily course of the two mentioned meteorological parameters. During the daylight part of the day, there is a gradual increase in wind speed and, at the same time, a gradual decrease in relative humidity. This suggests that dust blowing processes intensify in the afternoon compared to the facts recorded by satellite imagery.
The next research stage involved determining the temporal prevalence and frequency of the established meteorological conditions during different periods of the year. An archive of meteorological observations was involved, starting from January 1, 2006, and ending on December 31, 2018. The “Kryvyi Rih” meteorological station, in addition to the long-term program of meteorological observations, provides meteorological support for civil aviation flights. To support flights, the meteorological station transmits data on actual weather conditions in the area of the “Kryvyi Rih” international airport every half hour (sometimes more often). Since 2006, the “Kryvyi Rih” meteorological station has sent over 240,000 METAR code telegrams. For retrospective analysis of meteorological conditions conducive to extreme dust blowing from tailings ponds, I used data from METAR telegrams of the “Kryvyi Rih” meteorological station.
The analysis of meteorological data indicates that the most frequent favourable conditions for an extreme dust blowing from tailings ponds occur during March, April, and May. It is in the spring months that high wind speed, along with low air humidity, is most often observed. At the same time, meteorological observation data indicate a clear time-of-day dependency on these meteorological conditions. The highest number of cases of “wind speed 7 m/s and more” and “relative humidity 60% and less” is recorded in the afternoon, reaching maximum frequency at 4-5pm. This fact has specific practical application for public organizations and regulatory authorities: inspection checks of the effectiveness of dust suppression measures should be planned for the afternoon when there is the highest probability of high wind speed and the lowest humidity of the day.
A large amount of data allows for a more detailed analysis, namely, considering the frequency of the meteorological conditions of interest separately by the hour of the day for each month of the year. However, the results of such a detailed analysis do not significantly affect the general conclusions: meteorological conditions conducive to extreme dust blowing from tailings ponds most often occur in the spring and afternoon months.
How do wind speed and relative humidity generally behave without the limiting condition “more-less”? Analysis of the full set of meteorological data allows us to trace a clear daily pattern of changes in wind speed and relative humidity. During the daylight period, there is an increase in wind speed. There is also a clear gradual decrease and subsequent increase in relative humidity.
Having established the boundary conditions regarding wind speed and humidity, it is possible to identify days when such conditions were observed. To operate with days rather than individual observations, I selected those days when the maximum wind speed recorded during the day was equal to or greater than 7 m/s. Along with the previous condition, the condition regarding relative humidity was also applied – the minimum humidity recorded during the day was equal to or less than 60%. The result of such selection can be represented in a diagram, marking the days when meteorological conditions favourable for extreme dust blowing from tailings ponds were observed.
Now, having a “schedule of dusty days,” we can return to the actual verification of extreme dust blowing from tailings ponds… The virtual data storage and analysis environment, GoogleBigQuery, contains a complete and continuously updated list of satellite images taken by Landsat and Sentinel-2 series satellites. From the entire data array, one can select and save the names and parameters of images taken over the Kryvyi Rih region on a computer. By combining data on satellite images with the “schedule of dusty days,” we can mark those days when satellite imagery was carried out over the Kryvyi Rih region under our meteorological conditions of interest. The results of this analysis can also be represented in a diagram. The spring period is particularly interesting for analysis, as the above-described analysis of meteorological conditions shows that the highest number of cases of “wind speed 7 m/s and more” and “relative humidity 60% and less” is recorded in spring.
The only drawback of such a diagram is the lack of consideration for cloudiness within the satellite image. However, it visually demonstrates the possibilities of using satellite imagery to control the effectiveness of environmental protection measures at industrial sites. With the launch of Sentinel-2A and Sentinel-2B satellites, the frequency of satellite imagery over the Kryvyi Rih and surrounding areas increased from twice a month to 2-3 times a week!
I chose several spring satellite images from different years to verify the extreme dust blowings from tailings ponds. Assumptions about the dust blowing from tailings ponds these days are mostly confirmed – multi-kilometre dust trails are visible against the background of soils and vegetation.
The conducted research allows us to assert that the problem of extreme spring dust blowing from Kryvyi Rih’s tailings ponds has existed for many years. Throughout the entire time interval the research covers, dust trails from the tailings ponds of Kryvyi Rih’s mining and processing enterprises are recorded. The only exception is the materials from the spring of 2015. However, a detailed analysis of the meteorological conditions on April 24, 2015, indicates that during the flight of the Landsat-8 satellite (11:30 local time), the wind speed was 5 m/s, and the relative humidity was 62%. The increase in wind speed to 8-9 m/s and the decrease in humidity to 26% occurred in the afternoon. On the days when Landsat-7 and Landsat-8 satellites flew over Kryvyi Rih in March 2015, the increase in wind speed above the critical level (7 m/s) and the decrease in humidity also occurred in the afternoon after the satellite’s flight time. This also gives grounds to assume the presence of unrecorded dust trails in the afternoon.
The obtained facts indicate the low effectiveness of dust suppression measures and the constant unpreparedness of enterprises for specific spring conditions. Intensive dust suppression measures should be started not with the onset of summer heat but from when the snow cover melts. The distances of dust transfer recorded by satellite imagery indicate a significant environmental hazard posed by Kryvyi Rih’s tailings ponds. The damage caused by dust trails to the surrounding region can hardly be objectively assessed. However, I believe assessing the damage to soils is possible by conducting selective agrochemical passportization of agricultural lands.
But another problem arises before us! The gradual decrease in relative humidity in the region! According to observations of the “Kryvyi Rih” meteorological station, an annual decrease in humidity indicators can be suspected. Based on actual observations, Quantile regression predicts a steady annual decrease in humidity indicators. I associate this problem with global warming processes (without tying it to the causes of these processes). Suppose there is a gradual “drying out” of the air over Kryvyi Rih. In that case, this will lead to significant regional consequences – each lost percentage of humidity is hundreds of tons of water not received by the territory…
What problems will arise with the objects of the Kryvyi Rih mining-extracting complex as a result of global warming – one can only guess… However, it is no secret that the overall increase in extreme weather events (storms, droughts, abnormal annual temperature fluctuations, abnormal “instant” precipitation, etc.) will significantly complicate the operation of such objects. Are Kryvyi Rih’s industrial enterprises ready for rapid conditions change? Definitely not ready! The problem of extreme dust blowing from tailings ponds in the spring period, which has not been solved for at least 13 years, fully reveals the “degree of readiness” for environmental protection!
During the research, data from Landsat and Sentinel-2 series satellites were used. A complete list of satellite images over the research area was obtained using the GoogleBigQuery service. Meteorological conditions over the research area – Aviation Weather Station of the 2nd category “Kryvyi Rih” of the Ukrainian Hydrometeorological Center. Retrieval and analysis of meteorological conditions were performed in the R programming language environment. Graphic materials based on satellite images were processed using the geographic information system QGIS. Photos of tailings ponds were kindly provided by Eduard Horovyi (Public Association “Ecological Council of Kryvorizhzhya”). The translation from Ukrainian to English was done with ChatGPT and Grammarly. The original Ukrainian version was published on February 20, 2019.