Blasting restrictions are so tight in Europe that some operators were forced to abandon blasting in favor of using a breaker. Quarries in Italy, Spain, Sweden and some Eastern European countries have already made this move. Nobody is expecting this mining method to storm the country this decade, as The Beatles did in the 1960s. Yet, with U.S. communities trending toward more restrictive blasting, limited use of breaking, or selective mining, as an extraction method may not be too far off.

When blasting, mines break free a large amount of rock and then sort out the desired material. However, selective mining allows the desired material to be extracted with only a small amount of unusable rock being removed. Selective mining gives mine operators optimum control over their resources by allowing them to remove only the material that holds value and that the mine is licensed to extract.

There are three primary methods of selective mining: breaking, ripping and cutting. Breaking is the use of a hydraulic breaker to chip away at the desired rock deposit, producing a stream of material. When ripping, a ripper attachment is mounted to a bulldozer, dug into and dragged through the desired base material. Ripping is used to produce gravel or small fill material. Cutting is done with a surface miner and is used primarily for medium-hard rock, such as coal. As the surface miner drives over the surface of the material being extracted, a cutting drum chips pieces of material off the surface.

Selective mining methods are being used more frequently because increased regulations are making blasting difficult, if not impossible, in many European areas. Population is a primary cause of the increased regulations. Expanding cities and housing developments are growing into areas close to mines. And with people living and working close to mines, the shock waves, flyrock and noise associated with blasting cause concerns about residents' safety and the quality of life in these areas. Increasingly, U.S. aggregate producers are facing the same problems.

Many regulatory agencies and activist groups express concerns about the effects of blasting on wildlife and the natural environment. The effects of shock waves, flyrock and noise can disrupt many animal habitats, and the dust produced from blasting along with the ammonium nitrate and fuel-oil mixture present in many explosives often are linked to air and water pollution. This has led to tighter blasting restrictions

Additionally, concerns about the safety of mine personnel add to blasting restrictions. During blasting periods, mine employees are susceptible to injury from the explosives or debris from the explosion. These safety concerns make explosives expensive and hard to use due to close government control. Mine operators often spend a great deal of money to make sure their operations comply with the restrictions and regulations required for employee safety.

Before manufacturers designed breakers large enough to replace blasting, many mines located near populated areas were forced to close. However, the larger hydraulic hammers now available have allowed several of these mines to reopen.

Because blasting can uncover more material in a shorter period of time, it may be difficult for some to believe that in certain cases breaking actually increases the productivity of a mining operation.

However, by eliminating interruptions for blasting and clearing, breaking allows mining operations to continuously operate and bypass the secondary breaking process. As the hydraulic hammer breaks away at the face, it produces a steady stream of rubble. A single loader is then able to carry the material to a conveyer belt, which transports the material to the crusher. This system will improve productivity and save money by reducing personnel and equipment needs.

As opposed to the minimal equipment and manpower needed for breaking, blasting requires a hydraulic breaker for secondary breaking, wheel loaders to load trucks and several trucks to haul the rubble to the primary crusher. The wages of the employees required to operate equipment along with the cost of purchasing and maintaining large equipment is expensive. For excavator operators new to using breaking for extraction, specialized training will improve the quality of production.

However, technological advances in breaker systems make this process easier for operators. Breaking further reduces costs by allowing some mines to downsize or eliminate the primary crusher. An operation in southern Sweden uses breaking and is able to send its material directly to the secondary crusher — completely eliminating the primary crusher.

Minimizing the amount of waste material produced also decreases mining costs. Mine operators don't have to sort through blasted material and haul away the unwanted portions. Also, because blasting can be prohibited in certain areas of the mine where breaking is allowed, mines using breaking as an extraction method often obtain more yield from their approved mining volume.

Breaking can further increase the usable mining volume by reducing fines by as much as half. Blasting creates a shattering effect, thus producing small material. Conversely, breaking gives mine operators more control over the size of the particles because the operator controls the placement of the tool and the cycle time. Furthermore, when a mine blasts, small waste particles will often mix with the usable material, decreasing its quality and value.

The cost of using a breaker for extraction in the United States is about double the cost of blasting. Yet some of this added cost is mitigated by the reduced time and material wasted. One factor that offsets the cost of selective mining is the savings from not having to store explosives and comply with the necessary regulations. A long list of strict facility and security measures govern how explosives are stored. Many mines will spend large amounts of money on building or renovating facilities to properly store explosives and hiring security personnel.

And because breakers are less controversial than traditional blasting, breaking may simplify the mining permitting process. This can save operators a significant amount money and allow the operator to begin mining sooner.

This extraction method also can be used in underground mining. However, using a breaker rather than blasting underground will cut tons per hour produced by about 50%. This is about the same ratio seen when comparing these methods above ground. Surface mining production with a breaker will vary with the material type and the breaker used. However, 220 to 265 tons per hour is a fair production estimate for the breaking method.

Each mine is different, and a large number of considerations need to be made to determine if breaking is a good alternative for a particular location. Breaking instead of blasting isn't for everyone, but it can be an efficient alternative in smaller, more flexible quarries.

Breaker Mining Rate

Rock Type	TPH Range
Metamorphic: gneiss, phyllite, slate, marble	187 to 397
Sedimentary: platy limestone, sandstone	132 to 265
Sedimentary: limestone, graywacke, dolomite	66 to 198
Magmatic: lava, granite, diabase, basalt, gabbro, syenite, quartz porphyry	55 to 110