23.08.2024

 

Chronology of prospecting works at the Maikainzoloto JSC

 

 

Circumstances of the collapse and group accident that occurred on January 4, 2024 at the mine of JSC Maikainzoloto.

 

As follows from the Act of special investigation, on January 4, 2024, on the territory of JSC “Maikainzoloto” there was a collapse of the upper ground layer into the mine cleaning space with subsequent access to the surface.

In the cave-in zone there is a section of the technological road for delivery of rock mass from the Maikain site to the processing plant according to the approved in July 1, 2021 scheme of dump trucks movement, in accordance with the technological regulations.

 

 

At the call of the mine dispatcher, in accordance with the position № 9 (fire) of the accident elimination plan, the facility went to the two mine rescue teams of Maikain MMRS, serving this facility.

 

At 01:14 a.m. the first mine-rescue team, consisting of four people left on the operational bus for reconnaissance of the fire.

At 01:17 a.m. the second mine rescue team, consisting of four people left on a fire truck to extinguish the fire.

 

While driving the operations bus along the technology road to the area of the suspected fire, the bus with the mine rescue personnel inside fell into an existing dip.

 

 

Causes of the accident

 

The Commission, having considered the documentation, conclusions of expert, subcommissions and interviews with eyewitnesses came to the conclusion that the causes of the group accident are:

- industrial control over safe mining operations was not properly exercised by the responsible persons of JSC Maikainzoloto;

- the process of collapse of mine workings during mining of blocks was not properly controlled;

- no projects were developed for mining of excavation blocks during the development of ore body II above and below Mt. +90м (160).

 

The main hazardous production factor that led to the group accident was the collapse of the upper ground layer into the mine cleaning space.

 

The dimensions of the cave-in (surveyor's data) initially amounted to 176m in length, 130m in width, 67m in depth. Over time, the dimensions of the cave-in have changed insignificantly.

 

Search operations

 

Since the boundaries of the formed failure were unstable, the emergency area of the cave-in was cordoned off and access to it by unauthorized persons was restricted.

 

In addition to mine rescuers servicing the mine, were involved in the search work also rescuers of the regional department of the Ministry of Emergency Situations of the Republic of Kazakhstan.

 

At the initial stage of the search it was involved about 170 people, the work was carried out around the clock, with the involvement of three canine units.

 

On the first day two dead mine rescuers were found.

 

 

In addition, more than 40 units of various machinery, special equipment - geoscanners, magnetometers, two UAVs - were involved.

Soil was removed to lay a path for small-sized equipment to the site of the accident.

The movement and fall of pieces of rock mass were monitored from the edge of the slump around the clock. 

 

 

 

More than 200,000m3 of earth and rock were moved at the collapse site, including to lay a slope (ramp) to the suspected location of two more rescuers who remained under the rubble.

Heavy equipment laid a side ramp to the edge of the slump, which enabled the small excavator to be lowered to the bottom of the slump.

 

 

First, with the help of two bulldozers, a small-sized excavator (IHI50Z, bucket volume 0.25m3) was lowered to the bottom of the failure, which moved about 850 cubic meters of soil, thus expanding the space for the second excavator.

Then, with the help of two bulldozers, providing vertical and horizontal safety ropes, as with the first excavator, the second small-sized excavator was lowered.

To ensure the safety of the work, the roof of each excavator was dismantled and the excavator operator wore a special parachute-type device, which was connected by a safety climbing rope to a rope fixed on the surface on the sides of the failure.

 

 

In order to determine a more precise location of the bus, Maikainzoloto JSC engaged several third-party organizations with geo-scanning equipment.

At the initial stage, geo-scanning was conducted by specialists from JSC AK Altynalmas to coordinate the direction of the excavators.

 

 

Then, there was invited specialists of “Qazaq Geophysics” JSC of “Kazakhmys” LLP, who with the help of a crane with a telescopic boom together with rescuers conducted a survey of the sides and bottom of the formed failure with special geophysical equipment to search for voids, metal and other anomalies.

 

 

Subsequently, geo-scanning was carried out by specialists of GRP Ridder Group LLP, including the use of a drone.

The scanning results revealed anomalies caused by various metal objects.

In the drone photos, the anomalies are highlighted in red on the first section in intervals of 4-18 meters with coordinates shown below.

 

 

 

Throughout the entire period of search operations, the rescuers provided insurance and safety for two excavators and other specialists at the bottom of the sinkhole.

In compliance with safety rules, fuel, food, surveyors, as well as the lifting of found objects were carried out.

 Multiple fragments of the bus and personal equipment of the rescuers were brought to the surface from the excavation site.

 

 

 

Difficulties of the search operation and risks for its continuation

The search operation, throughout its duration, faced serious challenges due to very unfavorable weather conditions (low temperatures down to -30°C, strong wind gusts), extremely unstable soil conditions, significant cracks on the surface and in the collapse zone, constant soil falling from the slopes of the failure and the suspected presence of subsurface voids, which increased the risk of further collapses.

These factors posed a significant threat to the rescuers and, in the event of a potential collapse, would have necessitated additional rescue efforts.

The main problem was not the lack of manpower and resources, there was enough equipment and rescuers working at the scene, but in determining the actual location of the victims.

 

 

Consultations with foreign partners

Due to the fact that the search work took a protracted character and positive dynamics was not observed, the small-sized equipment used was ineffective, deteriorating weather conditions and increasing risks for rescuers working in the collapse zone, forced the leaders of the search work to turn to international experience of similar operations.

Through “Association of Emergency Rescue Services RK” LEA (a full member of the international mine rescue organization IMRB) were established contacts with foreign partners from Australia, Canada, South Africa, Russia, conducted online negotiations and consultations on the reasonable of further search operations and evaluation of the actions of Kazakh rescuers.

Feedback from foreign experts on the actions of rescuers from Kazakhstan - positive. A huge amount of work was noted, with the involvement of maximum forces and means.

Foreign colleagues shared their experience of search operations, sending detailed information and offered sound recommendations for the rescuers of Kazakhstan.

However, all foreign experts noted that the continuation of search operations in the existing conditions, maximize the risks to life and health of rescuers.

 

 

The world experience of search and rescue operations shows that in cases of high risk, real threat to life and health of rescuers, it is necessary to make a difficult decision to suspend operations or to stop them completely.

The leaders of the rescue operation at the mine of JSC “Maikainzoloto”, taking into account the experience of foreign rescuers and taking into account the risks of further search operations came to the conclusion that the best strategy may be the suspension of the search operation until the arrival of more favorable weather conditions, which will provide additional time to assess the situation and make more thoughtful decisions.

On February 5, 2024, after one month of search operations, the search operation at the collapse site was suspended.

In April 2024, the shareholder of JSC “Maikainzoloto” changed the general director of the enterprise and to assess the level of industrial safety at the enterprise and to resume prospecting and mining operations attracted the leader in the market of gold mining industry of Kazakhstan mining company JSC “AK Altynalmas”.

In May, a local project was developed to expand the trench (up to the +40-(60)m mark) and mining works were started to break the side in the north-eastern part of the failure to prepare the resumption of prospecting works.

At the same time JSC “AK Altynalmas” started searching for a special excavator with an extended (19m) boom. After negotiations this heavy special equipment was delivered from Ust-Kamenogorsk city to the place of resumption of search works.

 

 

In June, after repeated appeals of relatives of the dead rescuers, the company JSC Maikainzoloto said that they are ready to make an exit to the bottom of the sinkhole for the descent of heavy equipment and resume the search work.

The company also reported that in accordance with the schedule they carried out the necessary preparatory work.

With the help of special equipment was completed cutting and sinking of the trench to the +190-(80)m mark. Two powerful excavators were moved along the trench to the bottom of the sinkhole. Dump trucks removed and stockpiled 122,000 tons of soil on a temporary dump.

On June 28, the search work resumed.

 

 

Search work was carried out during the daytime from 5:00 to 20:00.

Once again cynologists with search dogs were involved.

The use of an excavator (cat250-0.6m3) with a long boom (22m) was crucial.

As the bucket of the excavator deepened, fragments of the bus body and equipment of the rescuers began to be found.

At a depth of 9-10 meters marked the hull of the bus (large circle), and after crumbling rock from the side of the failure found the body of the third rescuer (small circle).

 

 

 

The body of the third rescuer was found in the morning of July 19 at 06:15 hours, and raised to the surface 7 hours later, at 13:45.

Work on the extraction of the victim was complicated by the presence of a large boulder of rock above the body and he had to dig out manually, previously insured the boulder with a cable to the bucket of the excavator.

The body of the fourth rescuer was found on July 25.

At this point the prospecting works at the site of JSC Maikainzoloto were completed.