During both wars, mortar and artillery shells made in the 1950s and 1960s were fired into Grozny, with about a 15 percent dude rate. This leaves about 40 tons of explosives laying around the city. The rebels also used "written-off" shells abandoned by artillery units after they displaced from firing positions. The gunners were supposed to destroy dud shells, but more often than not they would simply dug out a ditch and buried the bad ammunition. There are about 30 such ditches in Grozny alone, holding an estimated 150 tons of artillery and mortar rounds.
Sabotage operations in Chechnya based on these field expedient mines sometimes take on a weird twist. Earlier in May, Russian intelligence learned that a rebel group was planning to blow up the railway near Usam-Kale and sabotage the withdrawal of Russian forces from Chechnya. A reconnaissance team was dispatched and spotted a group of people dressed in Russian uniforms working on the tracks. They did not look like Chechens and the Spetsnaz team concluded it was a rebel group, but decided to keep watching and wait for more rebels to lay mines on the tracks. Another Spetsnaz unit sent to the area saw more people dressed in Russian uniforms removing the explosives from the track, but additional land mines were found further along the train's route.
Military intelligence concluded that there were two rebel groups operating in the area: one wanting to blow up the train up and the other to keep the railway intact so that food could be brought into Chechnya. Federal forces later questioned of one of the rebel and determined that the group responsible for laying mines was led by Arbek Bari, who planned to blow up the train and a Terek River bridge.
Most encounters are more straightforward. For instance, a potentially devastating attack was prevented at the beginning of May when a string of command detonated mines were discovered and defused on Pervomaiskaya street in Grozny's Leninsky district. The ten mines were connected to a single switchboard system hidden in the ruins of an apartment building about 300 meters away. The homemade bombs included a 152-millimeter HE shell, a Grad missile launcher warhead, four grenades and four cans filled with explosive and nails (each can containing over about seven pounds of explosives). Pervomaiskaya Street is the city's main traffic artery and heavily used by both the military and civilians.
Major Yevgeny Pasynok, the chief of Grozny military commandant's office engineering service, estimated that there are seven or eight rebel groups specializing exclusively in planting mines around Grozny. He also figured that there's also a total of about 200 competent demolitionists operating in similar groups around the republic.
There are also 123 Russian minefields (from both wars) that have not been lifted in Grozny: 119 antipersonnel, two antitank and two mixed fields (antipersonnel and antitank mines). The majority of mines cannot be removed and despite being clearly marked, 592 persons were wounded in Grozny alone by mine explosions over the past three years. Russian forces also used aerial mining in Chechnya, with helicopter seeding in 1999 and the first half of 2000. The Staroshchedrinsky wood of the Shelkovskaya district, the mountainous part of the Nozhai-Yurt and Vedeno districts, and the Urus-Martan district's foothills were mined this way. - Adam Geibel
The main reason the rebels in Chechnya have enough explosives to continue harassing the Russians is because the Russians have left behind hundreds of tons of ammunition. About 90 percent of the command-detonated landmines are made from dud Russian shells, the rest are home-made devices.