Carlos Cavanillas, Drilling & Blasting General Supervisor and Ramón Arjona, Drilling & Blasting Senior Supervisor, explain the daily work routine for their area.
“We have a daily meeting first thing in the morning to check what the night shift is leaving us with; for instance, if there were any incidents or problems with the machines,” says Cavanillas. This is followed by a visit to the work- ing area for a general inspection. “We check the areas that are going to be blasted that day and determine wheth- er there will be blasting or not,” says Arjona, explaining that normally, blast- ing happens twice a day, at 2:00 pm and then again later on at around 6:00 pm.Veladero uses ANFO for blasting.
The severe weather can interrupt the operations. Indeed, as Cavanillas points out, they get an updated weather report every single day: “If there’s the possi- bility of a thunderstorm that day, we don’t blast - it could be catastrophic!”
Veladero’s current drilling fleet is composed of 11 diesel rigs, some drilling
To the left, the PV-271 is drilling 10 5/8” production blast holes at Veladero. Top to the right, Carlos Cavanillas, Drilling & Blasting General Supervisor (left) and
pre-split holes and some drilling pro- duction holes. This includes an Atlas Copco Pit Viper 271 and a ROC F9 unit. There are also four DM-M2 rigs amongst other machines.
The ROC F9 rig, which has been working at the mine about a year longer than the Pit Viper machine, is currently working in production, drilling small 4” holes. “It’s possible that we will use this machine for pre-splitting in the near future,” says Arjona, explaining that there is another ROC F9 unit, with similar configurations working on pre- split drilling at nearby Pascua Lama. “We’ve heard that machine is doing very well,” he says.
The PV-271 rotary drill is also work- ing in production. Before acquiring it, Cavanillas wanted to see a similar rig under working conditions: “Ramón and I went to Chile, where we had the opportunity to see the PV-351” he says, referring to the largest model in the Pit Viper series. Several of these units are working at Codelco’s Radomiro Tomic copper mine, 3,000 metres above sea level in the Atacama desert of north- ern Chile. They were impressed by the performance of the PV-351 and after discussions, decided that the smaller PV-271 was the best option for Veladero.
Pv-271 in action
The PV-271, which arrived at Veladero in May 2010, is currently deployed in Pit Amable drilling 10 ⅝” production blast holes to a depth of 15 metres. The mine employs standard 15 metre high bench drilling with a hole spacing of 7 x 8 metres in waste rock and 6.5 x 7 metres in ore.
A sturdy and powerful blasthole drill rig, the PV-271 features a pull- down force of up to 311 kN (70,000 lb) and a 34 tonne (75,000 lb) bit load capacity for maximum productivity in hard rock formations. Veladero has a silica-type rock whose quality varies throughout the site. “We have areas where the rock is hard, others where it is quite fragile and others where it is not only hard but also highly compres- sive,” says Arjona.
Victor Astudillo, the operator of the PV-271, knows this only too well. He
Other Atlas Copco equipment at Veladero includes a ROC F9 crawler drill rig.
duction blasthole can take anywhere from 18 minutes to one hour: “Most of the rock is hard so on average, it takes about 45 minutes to drill a hole.”
As all the machines in the Pit Viper series, the PV-271 uses Atlas Copco’s hydraulic cable feed system, which is lighter than the traditional chain feed option. This leads to overall weight reduction in the tower and feed system and to smoother drilling, which in turn extends both bit and feed system life. “Feeding and retracting for pull- down and pullback is really fast so I can spend more time drilling,” says Astudillo.
Astudillo, who has been a drilling operator for four years and has experi- ence working with the DM series, is pleased with the ergonomics of the rig: “it is amazing how comfortable it is. There could be dust and noise outside but you barely feel it inside here,” he says, adding that he also likes the fact that the drilling and non-drilling con- trols are separated: “it certainly makes the machine easier to operate.”
Working at high elevations can present a number of problems for any machine. With every additional metre in elevation, air density and pressure decrease and traditional electronic components no longer function reli- ably. “Also, our severe winter can affect a machine drastically,” says Arjona, explaining that some areas of the machine such as the air and water circuits can easily get frozen. So, in order to work under the weather condi- tions at Veladero, the PV-271 had to be equipped with several special features such as a more powerful engine and compressor but also with a cold weath- er package, which includes additional covering of the machinery housing and allows for warm start-up and drill operation in extremely cold ambient conditions.
And how has the PV-271 faired in this harsh environment? “Oh, very well indeed and with good reported availability times, too,” says Arjona, explaining that when comparing forecast versus real availability and utilisation in the monthly report, the real figures normally come on top.
“The PV-271 has given us good levels of availability. We can rely on that machine, and for us that’s what’s important,” says Cabanillas.
According to Fornés, when choos- ing new equipment for the mine they take into account some basic param- eters, such as the machine being able to be fitted with specific features for cold weather or the machine’s penetra- tion rate. But in the end, it is the total cost of owning that machine which is going to tip the balance for Veladero: Cost of buying the equipment itself, cost of operating it and cost per hour. “Whichever equipment gives us the best results, that’s the one we’ll go for and in this case it was the Pit Viper 271.”