Since the beginning of mankind, there has been mining. Man searched the hillsides for obsidian for making points and the stream beds for rocks suitable for hammers or clubs. King Solomon, of Biblical times, had iron, gold, silver and turquoise mines. His miners used moil, hammers and fire to chip and spall the rocks. The early Romans mined in all of those areas which they had conquered. Their mining methods were similar to those of King Solomon’s day, except by this time new tools of iron were available.
In the mid 1880’s, miners were hand steeling and using black powder to blast the rock. By the late 1800’s and early 1900’s, steam power, electricity and compressed air were available. Mining was becoming simpler with less manual labor involved. Today, mining is highly specialized, using diesel, electric, gas or compressed air to power all types of mining equipment. The 21st Century has brought us a new tool with which to mine. Lasers will replace drilling and blasting methods that are presently the standard in the mining industry. Finally, man has come full circle, from spalling rock with hammers and fire, to now spalling rock with the power of lasers.
Modern technology and innovative thinking have combined to provide a creative new way to mine underground. By utilizing lasers for spalling (breaking) rock underground, lasers will eventually eliminate conventional methods of drilling and blasting. Preliminary test work indicates substantial savings can be realized in time, material costs, and operating costs.
This new mining method involves the use of high optical power output fiber lasers to cut or spall ore bearing material from the host rock. Because the spalled material is in the form of “pea” sized chips, these chips can easily be moved from the working face to the surface. A milling advantage is that these small chips do not require crushing and can be discharged directly to the ball mill or leach pad. Merger Mines Corporation is developing a single head laser mining device (Phase I) for use as a characterization unit for underground mines. Once the operating parameters of the single head mining unit are established, other laser mining units can be developed for narrow veins. The single head laser mining unit (Phase II) will be used for such narrow high grade veins. The mining width for this unit will be just over two feet. For example, a four unit laser mining array (Phase III) would work in an eight foot wide vein. With the experience gained from the mining program, laser mining heads will be mounted on mobile equipment and used for driving drifts and development headings. Plans are also in place for driving raises, either bald or timbered. Not presently under consideration, but certainly not ruled out, is the sinking of mine shafts.
In underground mines, lasers will reduce operating costs substantially. Jacklegs, drill steel, bits, powder, blasting caps and a multitude of small tools can be eliminated from normal stopping costs. Labor costs for mining and material costs will be greatly reduced. Underground supervision will be simplified and overall mine safety should improve. Plans are in place for a laser mining unit using a one or two person crew to operate multiple working faces from a central control module.
Many mines today are facing adverse environmental conditions underground. These conditions vary from mine to mine, but depth, temperature, water, and pressure are the key problems encountered by many. The miner is affected by all of these, but the laser can operate in this environment.
The mining industry today is in desperate need of new technology. Annually, mines are closing because of declining head grades, increasing labor and material costs, lower grades due to dilution, and adverse environmental conditions encountered underground. Lasers will not solve all of these problems, but they will help to turn marginal mines into profitable mines.
This material has been re-produced with permission from Merger MInes Corporation.