Choosing the hardware and software for high-tech surveying systems is a lot like buying a stereo system. The question is this: Do you stick with one manufacturer for all your components or do you “cherry pick” and integrate the best components from a host of sellers? Engineers at the Kidd Creek mine chose the latter course. Here’s why. * * * The laborious technique familiar to all mine surveyors — repeatedly transcribing theodolite data, followed by manual computation, unit transformation and representation of results — can now be replaced with computerized tools. These high-tech tools provide automatic capture and manipulation of survey data as a singular field process, followed by reporting and plotting. Electronic theodolites, however, are generally expensive, have more bulk and are less robust in comparison to conventional theodolites, and available software for manipulating the data are poorly adapted to underground mining applications.
While numerous products purportedly provide a total survey station facility for mining, we’ve found that few of these offerings apply to the underground operations at Falconbridge Ltd.’s Kidd Creek mine in Timmins, Ont.
Many vendors claim that increased throughput of survey work justifies buying their products. In some cases, this may be true. But our research indicates the money spent on modern electronic instruments can be put to better use providing transportation facilities to technicians, allowing them more time at the conventional transit.
While improvements in office practise are afforded by packaged vendor offerings, these are so difficult to learn and precarious in their operation as to almost negate their time-saving features. For a much smaller investment in capital, the Kidd Creek system, we believe, is equal to the single-vendor product for underground surveying, and it’s easier to learn and more user-friendly.
The successful implementation of the total survey station concept at Kidd Creek in late 1987 was very simple and relatively inexpensive. (Although the system is not in the final version, it is in a usable format.)
While Falconbridge’s base metal operations in Timmins are not ex panding in tonnage hoisted, the mines are (as within any mature workings), ever increasing in logical and physical complexity. For example, in 1979, No. 2 Mine had no production below the 2800 Level, but during 1989 pro duction is planned above the 4600 Level while still proceeding on the 2800 Level. With this increase in mine physical dimension, the distances that surveyors must travel has become excessive. At Kidd Creek, as in most under ground mining operations, survey crews travel to the work place via the cage and they walk or descend some combination of ramps, drifts, cross- cuts and so on before reaching the place to be surveyed. They take readings from instruments and record them on field data sheets and subsequently repeat some reverse order of their steps to move to the next survey area or ultimately return to the sur face office. To increase survey crew effectiveness, it was found modern ization of underground survey prac tice was necessary. Since the majority of the survey crew’s time was spent in travel from workplace to workplace, some form of rapid mobilization was required.
The costs of maintaining skilled survey technicians must be weighed against the actual time that these individuals can be employed in carrying out their function. After studying the amount of time that each survey crew spent travelling on their beat, it became obvious that providing these crews with small diesel tractors would net an immediate 40% gain in the amount of actual surveying performed per day.
While this form of transportation is common in most LHD trackless mines for the purposes of supporting the mine production and maintenance functions, it is usually not applied to survey or geology field technicians. The movement of men and materials on mechanized carriers is usually restricted to specific locations and times during a typical shift. As survey technicians generally try not to interfere with production functions in the underground, efficient use of this equipment in support of their more or less random logistical movements was not feasible at Kidd Creek.
Further study of the economics involved showed that the purchase of two tractors dedicated to the survey function would show a payback of less than three years.
Using conventional survey instruments, the technician keys field observations and notes into a program- operated data collector, at the point of an underground survey; the data collector verifies or indicates discrepancies within the observations and provides the technician with feedback of survey computations; based on the results, the operator may then choose appropriate action; at the appropriate time, the collected observations are uploaded to the Apple Macintosh micro-computer, manipulated, checked, archived, printed in field sheet form, plotted to scale and, optionally, transmitted as data to other computer-based software systems.
The instruments used are highly reliable wild ti-a theodolites, favored by the survey technicians. While a field data collection unit is not available for direct electronic interface to the instrument, keystroking of pertinent data via a structured, yet flexible, entry protocol is possible, given a portable, programmable and self-contained micro-computer. This method of data capture, while not as automated as the newer electronic theodolites, would prove almost as effective, even though manual data entry is required to capture survey informa tion within the mine workings.
Three types of portable data collectors were tested during the span of the project. These included the videx Time Wand, Hand Held Products microwand ii and the Hand Held Products Advanced Pocket Computer (also marketed as the Psion Pocket Organiser ii). Both the Time Wand and microwand ii have desirable features as concerns data collectors, but both failed endurance tests in the underground environment because of condensation dew point.
The Psion Pocket Organiser ii hand held computer was chosen as a suitable electronic field data collection unit. The Psion unit can be configured with various memory sizes, has a multi-purpose peripheral port capable of interfacing to rs-232c-com patible devices or to a bar code reader wand, two-line by sixteen-character liquid crystal display and a full ascii keyboard. The unit is housed in a self-contained plastic case no bigger than a Sony Walkman (about three by five by one inch) and weighs eight ounces. It is powered by a 9-volt replaceable battery.
Programming of the data acquisition procedure was accomplished through the basic-like computer language provided with the Psion unit. Thus, field data is assembled into electronic records, analogous to entry lines on the paper-type records formally used by the survey technicians. These electronic records may then be transferred over the rs-232c asynchronous communications link to any type of computing equipment, for further processing.
Menu-driven programs integrated with “help” tutorial texts on procedural functions has helped to train new users on the pcl program.
While almost any computer system could be used to receive data from the Psion data collector, the choice of the Apple Macintosh was the most appropriate at Kidd Creek. Data within the Psion Pocket Organizer ii is transferred by direct or modem link to the Macintosh operating under a general communications package (Palatir InTalk) as an ascii text-type file. Each record in the file consists of 33 variable-length character fields, separated by tabs. Each record represents one complete set of survey observations relative to a single setup.
Three off-the-shelf, vendor-sup plied applications form the nucleus of the host computer data manipulation and display system. These include generalized packages for data communications, spreadsheet calculation and database archiving and computer- assisted drafting. Employing the Apple computer-supplied switcher application, a user can load all three applications on to the host Macintosh system at the same time. While only one application can be active at any time, data conversion facilities within switcher allow the user to rapidly transfer data between any permutation sequence of the three applications. In this way, the three main functional components of the nucleus software can be integrated into an apparently contiguous and singular system.
While the merits and deficiencies can be argued amongst a host of other products, these three primary packages best accomplish the goal of automating surface survey office opera tions at Kidd Creek.
Through the use of integrated user- friendly macro programs operating on a spreadsheet, a database of sur vey point information has been constructed. The salient features of the Excel Macro program design include the facility to:
* Read field observation data transferred from the data collector, or manually entered information.
* Retrieve coordinates and eleva tion of previously stored stations necessary for the trigonometric conversion calculation of observations into results.
* Automatically store the results as a simple sequential list of database records, by station name.
* Provide printed reports of field observations and calculation results as per excepted engineering standards as well as by ad hoc database query.
* Automatically update, demand edit or query the database by any data criterion.
* Calculate co-ordinates of all survey points (including topes), and provide output in a format compatible with the Minicad graphics system.
The surveyors employing this system have had little difficulty in assimilating the technology. Through the use of pull-down menus and question windows, this application appears only slightly different than the type of interface employed within the data collector. In this way, a consistent user interface has been achieved.
In a related vein, in 1986, a study was conducted to ascertain the extent of blast fragmentation and its rela tionship to blasthole placement and orientation. One of the basic findings was that hole deviation had a signifi cant effect on fragmentation. Indeed, no matter how elaborate the instru mentation employed to insure that a hole was aimed in the proper direc tion and regardless of what equipment was used to maintain direction, blast holes deviated from what the mine planner had envisioned in layout. Unless a blasthole becomes a survey able break-through, there is no cer tainty of what orientation it has assumed. The associated additional mining costs and grade dilution attributed to poor fragmentation can mean a rather sizable difference in operating costs. Time Savings
Considering the time savings that are afforded through the moderniza tion of conventional underground surveying, the purchase of an instrument capable of surveying blastholes would simply become another tool for use by the survey technician, at no addi tonal cost in manpower.
Owl Technical Associates was in vited to demonstrate its OTA Borehole Directional Survey Tool. The instru ment was reportedly capable of pro viding an exact geodetic survey of a borehole and thus appeared amenable to the blasthole deviation problem.
The OTA survey system consists of a probe containing instruments capable of sensing inclination and direction; a winch for lowering the probe and its electrical umbilical (complete with a metering distance device), safely and securely; a console contain ing the circuitry for operator controls, visual data and control display, ther mal printer output, and serial output port.
The console provides for the calculation of results such as probe direction, true vertical depth, distance north, distance east, net horizontal distance and net bearing as well as the capability of compensating for decli nation.
An OTA survey tool with the following custom modifications was purchased:
* Provision of an environmentally protected case to isolate the console electronics from the rigors of the underground.
* Provision for electronically capturing data ouput by the instrument as an ascii text file.
* Conversion of the winch to electrical power and of a more robust design.
* Provision for the system to be completely powered by 12-V dc and mountable on an underground service tractor.
The data collector field observation information provided by the survey tool is transferred to the Apple Macintosh host computer system. Excel-manipulated data may be reported or alternatively transformed for plotting by Minicad.
The modified instrument system was received in mid-1987. After a number of initial problems were worked out on surface, the instrument was mounted on a small tractor and sent undergound for initial testing on a hung-up orepass. In order to blast the hang-up, it was necessary to drill a 270-ft hole that was to intersect the orepass at the location of the hang-up. The hole was drilled with a Robbins model r11d but did not break through. The hole was surveyed using the borehole directional survey tool and it was determined that the hole had deviated some 20 ft from design. The next hole was laid out allowing for the deviation previously deter mined. The hole broke through into the orepass, was blasted and the hang-up knocked down.
Over-all, Kidd Creek has found that introducing modern methods into un derground surveying has not reduced costs, but it certainly has enabled the survey department to substantially increase the workload. For example, the department is now surveying blast holes, an operation that surveyors didn’t have time for in the past. Alfred Yetter is senior mining engineer; George Hughes is technical specialist at the Kidd Creek mine, Timmins, Ont. — 30 —
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