Shotcrete Red Hot in Peru

An1amina copper mine is a Sl.2 btltion projcc1 in lhe Andes Mountailh of Peru. The projeci. owned by Canadian mining gi3111S Norandll. J’cck and Rio Afgom, i.s one of the. single largest mining inveso:nents in 1be Americ:iô€€£ at this moment and oomprises the cons1ruction of an open pi1, a co11veyor runnel, a tailings dam. a mill and pon facilities for ¢1’por1 of processed concenlrllle all over the globe.

Moab Khotsong Mine, Part 2

Having discussed the basics for the successful application of SFR wctcrete, the issue of its quality maintenance needs to be addressed. There are a num­ber of critical indicators that the placed product has to meet.

Performance of Dry-Mix Shotcrete in Permafrost Environment

In order to achjeve the objective. it was impor­tant to develop a mix lhat would rapidly generate a high heac of hydration. The cold ambient air would cool down 1he shotcrete but the heat released dur­ing the hydration process would allow 1he hydra­tion of ccmem 10 proceed unril Lhe remperature of fresh shotcrete decreased lo the freezing tempera¢ ture of the brine solution (brine is a solution of cal­
cium chloride). Al that 1empera1ure, brine freezes and the process of hydration remains suspended until thawing takes place. A laborntory test progi-am (not presented in 1his paper) was used to develop two dry-mix shotcrcte mixes for performance evaluation at a mine near the Arctic Circle under permafros1 conditions. The mixes evaluated had very shon initial and final set times. generated the most heat of hydration during the first 1rtinu1es, and developed the highest com­pressive strcnglh during the first few hours.[2] It. was lherefore. expected I.hat these mixes could be ap­plied on frozen surfaces and would be able lo set and develop adequate mechanical properties.

Making Dry-Mix Shotcrete Go the Distance Underground

Dry-mix shotcrete as a means of grouad support for lunnels and mining drifls is fasl, eflicient, and very safe when properly applied. lls effecliveness is unmatched: I can remember lining unstable clay mining tunnels (drifts) using a layer of shotcrete, wire mesh, and another layer of shotcrete. The arrival of steel fiber shotcrete made life even easier, taking care of severe ground conditions.

Shotcrete: A Key to Advances in Safety and Productivity in Mining

In 1969, when I bid farewell to work in field exploration, I knew I would miss the outdoors. I wasn’t sure if my love for geological mapping, and my penchant for using geophysical equipment to probe the earth for her riches, would be fulfilled. The truth was, I embarked on my new career in an underground mine with a major metal mining company seeking the opportunity to be at home with my family in the evenings and to have access to a university to complete my BSc in Geology.

Shotcrete in North American Underground Mines: Yesterday, Today and Tomorrow

Carl Akeley began the process of guniting, or what is now known as shotcreting, sometime around 1907. Since shotcreting subsequently found its way into underground 1uining operatio1t.s. ii has unc.lcrgone an evolution through the 20th Cen­tury Lo where we find the process being used today in North America and elsewhere. in mining around the world.As we look al 1be progress.< of sho1crete in Nonh AmedcM underground mines. it becon1es useful ro break down the pn)CCSS into five distinct parnmetcrs: mix design, equipment. logistics, applications, and operalors; for discussion (>f each.
While Some of our current practices have es1ab­lishcd a benchmark for others to emulate, we also stand to leam from the practices of the resl of lhe
mining world. However, what ever perspective one takes of the current state. of affairs, is an important pan of ground support in modern mining applications. and its use and effec1iveness wW con­tinue to grow as we. tackle the chaBenges that min¢ ing brings us in the 21¢ Century. Sbo1cre1e. or sprdyed concrete if one prefers, hos a bright future

The Use of Steel Fiber-Reinforced Shotcrete for the Support of Mine Openings

What separates the support of mining open­ings from the support of similar civil engineering structures is the fact that mine openings have to survive large defonnations as a result of changing stress conditions induced by progressive mining. Steel fibers impart to concrete and shotcrete a high degree of ductility which not only allows the shotcrete and concrete linings to absorb important rock movements, but also to increase their bearing capacity by a redistribution of the loads.
The use of shotcrete for the support of under­ground excavations was pioneered by the civil engineering industry. In recent years, the mining industry ha,;; become a major user of shotcrete for underground support. The simultaneous working

Steel Fiber Reinforced Shotcrete, It is time to find out about it.

In an age when the building, tunneling, and in some areas, min­ing industry, is thriving in North America, we in the shotcrete industry should be looking for ways to increase productivity and save on ever-increasing labor costs. This type of thinking often requires the use of products that we either are not familiar with or have never used at all. Since we are in an industry where our chief concerns are keeping a safe workplace, while at the same time, trying to increase production or speeding up project comple­tion time, we are often times unwilling to try new technology because we are afraid of the unknown. We fear a decrease in pro­duction, having to buy new equipment, and worst of all, lost­time accidents.For this reason-the unknown-many shotcrete contractors and mine managers have shied away from the use of steel fibers in their shotcrete. Their arguments against using steel fibers are often the same. “We use mesh or rebar for reinforcement because we know for sure that the reinforcement is in place before we apply shotcrete. That way, we don’t have to worry whether or not we have added the correct amount of steel fibers, or if the steel fibers are mixed uniformly, or if the fibers will do the job at all.” Or, we hear the all too familiar response, “If it is not broken, don’t fix it.”
In my opinion, this “if it is not broken, don’t fix it” attitude is keeping a lot of shotcrete contractors from increased production and greater financial successes. Sure, the economy in North America is strong now in the