Lacking experience in core drilling, we enlisted the help of specialists from a large Balkan company with extensive experience in diamond drilling. We organized the arrival of foreign drillers and their assistants, and on October 26, 2019, we started working.
Each machine drilled the first 700 meters in about 20 days, showing a mean-shift (12 hours) rate of drilling of 35 linear meters. Geologists did not have time to describe the core, which had to be taken out by truck.
However, the deeper we drilled, the more serious the faces of the drillers became... and not without reason.
So, what did we face and what did we have to go through?
At depths of 700 meters or more, we were expected to find fractured zones, abounding in aquifers and various types of falls. Foreign drillers were perplexed, threw up their hands and muttered something like: "I have worked as a driller for 30 years, in which countries I have not drilled, but I have never encountered such problems!".
All these problems were compounded daily by a severe cold snap. The beginning of winter was extremely severe. We made insulated drilling buildings in the shortest possible time, hiding from the storms and frosts. To protect the rollers of the mast from freezing, and the workers from the winds, we invited a specialist who made caps for masts from tarpaulin in Yakutia. Based on the patterns provided by the "Yakut" specialist, we sewed two caps for the masts and under the close supervision of the professional, we safely "dressed" the masts in an impenetrable tarpaulin.
The specialist was satisfied with his work and gave a guarantee that the soft construction created by him will serve us for a long time, faithfully. But the Khromtau snowstorms thought otherwise, and in about a week we were removing the remnants of that expensive experiment.
Bad weather and geological complications affected the mood of foreigners and they increasingly looked towards Europe. And already on December 22, after working for only 2 months, our Balkan colleagues hastily retreated, not promising to return, trying to make it before the closure of the highway due to a snowstorm.
This was the next challenge, as we had to quickly form a team of resident specialists, and put into practice the skills of local content.
Our new team set to work with enthusiasm, and an important factor in understanding each other was the absence of a language barrier.
In one of the boreholes, in stages, we poured cement with a total weight of more than 13 tons. At the same time, we organized a whole laboratory in the drilling building, where we made more than 10 different types of cement mixture by trial and error, using various intensifiers, hardeners and cement grades.
When we resumed drilling the borehole after cementation, at a depth of 846.0 meters, we encountered a new problem called "quick clay". This is a gray clay mass that floats on the drill pipes in an endless stream, forming an oil seal plug during drilling, while losing circulation and rotation.
It was decided to pass this interval dry, scooping out the clay mass in baby steps. Like air, we needed a chemical reagent that would help us pass the quick clay much faster, and we also needed spare parts for machine tools, but at that time a pandemic was raging, immobilizing the transport corridors connecting the states.
After about a month of our efforts, a long-awaited package with a reagent arrived in Khromtau, which allowed us to pass the "quick clay" in the shortest possible time and soon we were able to reach the chrome lode. Here the most important thing was not to stop, as sticking could happen at any second.
On April 22, 2020 (at 16:00 Nur-Sultan time), we managed to reach the coveted design depth of 1,170 linear meters. Our joy knew no bounds. We did it! But we did not lose our concentration, as there was still the geophysical research (logging) ahead.
It was our first big win!
Having slaughtered another black sheep before starting drilling, with a prayer to the Almighty, we began to drill the next borehole with a depth of 1,170 linear meters.
Soon, this borehole was conquered by us, not forgetting to throw new curves.
All those who somehow contributed to the completion — geologists, geophysicists, and colleagues who drilled nearby — were asked to our dastarhan. We are all in the same boat and each person is important.
Summing up the results of the outgoing year of battles with geological complications, bad weather, coronavirus, we can conclude: we were challenged and it was a matter of honor for us to win. It is also obvious that from an economic point of view, we did not make a profit, but we gained tremendous experience. Our guys have mastered the core orientation, inclination, built their bi's by the up and down operations, demobilizations, learned to fight to the end, overcoming various barriers.
Yes, we have something to strive for, but now, looking at holes with a depth of 500-700 meters, we smile, because we know how to cope with them.
We overcame two boreholes, setting a record at the Almaz-Zhemchuzhina deposit, and coped with many difficulties that arose on our way.
Now we are ready to conquer the undiscovered deposits of our vast motherland.
Editor-in-Chief and founder of Drilling Solutions