New Analyzer Service Brings the Lab to the Mine

Combining XRF technology and an Internet-based remote logging system, MOLS provides sample analysis results in real time

By Steve Fiscor, Editor-in-Chief, E&MJ

Sampling for exploration and grade control purposes can be a time-consuming process. Typically, a drill core has to be shipped to a lab for analysis. The cores, which are awkward, have to be handled properly, identified and logged into a system based on depth and location. Depending upon the region and the current state of the mining business, getting the results from this process could take as long as several months. And, if a mine is using this information for grade control, the delay could lead to unnecessary drilling costs to say the least and perhaps increased dilution in the mining process. The long lead time for results could also jeopardize a bankable feasibility study.

About two years ago, a Finnish company, Mine On-Line Services (MOLS), had a bold idea. Using X-ray fluorescence (XRF) technology to provide online elemental analysis, the company embarked a plan to build a mobile lab that could operate at the mine site. If they were correct, the mine would gain nearly instant access to analysis data, enabling a reactive exploration drilling program. MOLS soon launched its Scanmobile, which does just that. Being able to analyze samples onsite, however, is only half the process. The mines also need access to the data in a timely fashion. For that, MOLS developed a remote logging (RemoLog) system, where reports are often available the next day via an Internet browser.

According to the company’s President and CEO, Ilpo Auranen, the basic premise behind MOLS was to use modern technology for onsite mineral analysis. “This idea developed after 30 years of drill core analysis,” Auranen said. For 18 years prior to founding MOLS, Auranen worked with Metso Minerals and spent the last eight years as the mining technology manager. In that position, he was analyzing the mining process trying to find areas where value could be created. He had been working with XRF technologies since the early 1990s. One of the biggest benefits to XRF is that it can determine the elemental content of the ore without destroying the samples.

“In the mining business, traditionally the focus has been to lower the cost per ton, but few people are determining the value of the material being moved,” Auranen said. “Rather than a cost-driven mine plan, the mine could take a more selective approach based on the value of the rock, if it knew the grade at a certain location in real time.”

Real Time Mineral Analysis

Online XRF analysis works well with drill cores and it does so quickly. The lead time for traditional drill core analysis, Auranen explained, is considerable. “In Finland, for example, it could be done as quickly as several weeks or it could take as long as several months,” Auranen said. “Meanwhile, the drillers keep drilling and sometimes in the wrong areas because they had not received the results from the analysis.”

Bringing the lab to the samples shortens the handling time and would improve a rather inefficient process, Auranen explained. “We decided to install this system in a mid-size van and process the samples on the spot,” Auranen said. “Soon it became obvious that we needed to transmit the information faster. So, we developed an Internet-based browser where the mines can access the results in almost real time. We are using several step changes in technology to shorten the data delivery time.”

In December 2007, the Scanmobile began making its first trips to the mine sites as a moving laboratory with an on-line XRF analyzer onboard. Technicians in the Scanmobile scan the cores in the box before they are logged into RemoLog, which provides a report that includes the elemental contents as function of the borehole length. In addition to spreadsheets and graphics, the system can provide high resolution photos of the core box as well as the individual core’s surface texture.

Being on site, MOLS technicians collect the samples from the borehole directly and then, once the lab returns the analysis, they recalibrate based on those results. “We have a number of XRF analysts that understand the technology well,” Auranen said. To date the MOLS team and the Scanmobile have processed samples from calcium carbonates (and oxides), low-grade nickel, silver, gold, copper and zinc, and apatite ores. In addition to drill cores the Scanmobile has been working on projects analyzing, drill cuttings, and rock and till samples.

XRF for Grade Control

So far, the technology has been used mostly for grade control where a certified lab analysis is not necessarily required. Instead of a geologist, a mineral analysis specialist reviews the data. “We cooperate with the mine’s geologists,” Auranen said. “We have been developing the system in cooperation with mine geologists in Finland. The mine gets the data right away and then they certify it with compliance standards.”

During the measurements, normal laboratory procedures are followed. The XRF analyzer is calibrated for each application with known samples. The accuracy, analyzer performance and repeatability are calculated during the calibration procedure for each element.

Even though this application of online XRF technology has not been certified yet, Auranen believes that it’s only a matter of time. “We adhere to the same principles as a traditional lab analysis,” Auranen said. “We calibrate the analyzers toward certified lab samples. Actually, we analyze the samples and then recalibrate the results based on certified results afterward.”

According to Auranen, the mines have accepted the accuracy of the XRF analysis. “That was the first obstacle we had to overcome,” Auranen said. “The results compare well with lab analysis results. They are also obviously happy with the turnaround time.”

The system is designed so that the technicians can log the cores on the RemoLog browser. Mine geologists can log into the server and view the results. The analysis reports include an Excel spreadsheet along with a graphical representation. Another great attribute is that all of the information can be entered at one central location.

Presently, the MOLS team has one Scanmobile and they have been operating exclusively at the mines in Finland, but they do plan to expand. “This is a service-oriented business and we have to a high enough volume to justify the expansion,” Auranen explained. He hopes to expand to Sweden soon and eventually to mining markets in North and South America. In fact, MOLS is currently looking to partner with another company on expanding the service.

In addition to providing, geochemical analysis services for mining and exploration companies, MOLS consults on selective mining. The company also has cross-belt analyzer for run-of-mine ore. “Using our services, the mines would have access to in-house sampling and analysis without a big investment in equipment and human resources,” Auranen said.

Auranen believes that online XRF technology can be used to test anything. “We have been working mostly with drill cores,” Auranen said. “We have also been developing a system for analyzing drill cuttings. We are determining the best way to take the sample and pack them so that they can be properly analyzed.”

The MOLS is also experimenting with laser-based technologies such as Laser-Induced Fluorescence (LIF) and Laser-Induced Breakdown Spectroscopy (LIBS). The LIF method detects minerals, as opposed to elements, from signals that illuminate from the molecular structure. According to MOLS, the LIBS method detects the light and actually nearly all elements by vaporizing molecules and triggering a signal. “We are also studying other methods such as infrared which uses different wavelengths of light,” Auranen said.

The Scanmobile service offers new possibilities for enhancing exploration drilling projects. The combination of the rapid on-site analysis it provides and the real time access to data and core images through RemoLog, could have a profound impact on how geologists approach their projects. The logging system puts all of the information in front of the mine’s geologist in a concise format that is accessible via the Internet. With the analysis reports readily available, the mine can adapt drilling plans in real time.