Proceedings of the 7th World Congress on Mechanical, Chemical, and Material Engineering (MCM'21)
Prague, Czech Republic Virtual Conference – August, 2021
Paper No. MMME 114
DOI: 10.11159/mmme21.114

Analysis of the Surveying Errors in the Cabanasses Ramp
BreakthroughLluís Sanmiquel1, Marc Bascompta1, Hernán Anticoi2, Nor Sidki1
1

Department of Mining Engineering, Industrial and ICT.
Polytechnic University of Catalonia (UPC), Avenue Bases de Manresa, 61-73, 08242-Manresa Spainlluis.sanmiquel@upc.edu; marc.bascompta@upc.edu; nor.sidki@upc.edu
2
Department of transportation and process project technology.
Polytechnic School of Mines and Energy (UNICAN) Boulevard Ronda Rufino Peón 254, 39316-Torrelavega Spain
anticoihf@unican.esExtended Abstract
The Cabanasses Ramp is a complex tunnel designed to access the Cabanasses Mine and improve the environmental
conditions, safety and production capacity. Its construction started in July 2012, finishing in 2020. Until now, the only accessto the Mine was through 2 mine shafts called “Pozo 2” and “Pozo 3”.
The Cabanasses Mine is located in Súria (Bages, Catalonia, Spain). The Ramp will be about 5.1 km length, descending
more than 800m with a high gradient, with a maximum slope of 21%. One the first surveying works carried out during theconstruction of this ramp was the transmission of the orientation and cartographic system, between surface and undergroundworkings, by means of the vertical shafts. In the study [1], it was assessed the accuracy of this operation in a case study using
the two-shaft plumbing and gyroscopic methods in order to compare and analyze the planimetric displacement of the baseline
due to different sources of error in each method.
The second group of topographic works were the planimetric and altimetric polygonal surveys that were carried out inthe mine branch and the advance branch from the outside. It is important to note that from the mine branch, only 0.5 km wereexcavated, while the rest of the ramp, 4.6 km, was excavated from the outside branch. The ramp in the mine started near theINT11N-INT10N base located about 3 km from the entrance shafts, and about 600 m from the breakthrough (meeting pointof the ramp between the outside branch and the mine branch). It is well known that some errors are always found in theplanimetric and altimetric polygonal surveys. In fact, several studies indicate that these errors are due to the propagation oferrors in the measurement of angles and distances at each station of the polygonal [2, 3]. Moreover, these errors, especiallythose related to planimetric orientation, accumulate as the polygonal is progressing.
In short, there was the need to carry out two closed polygonal underground chains, one along the outside branch and theother one in the inner branch to achieve the breakthrough from both sides. Several gyroscopic observations were required toverify and control the accuracy of the topographic results obtained. The usage of a gyroscope survey is a method widely usedin the transmission of the orientations to underground works [4]. This information is crucial to avoid the effect of lateralrefraction and all the errors that can be generally accumulated in underground surveying.
The surveys done for the breakthrough were validated on the 21th of December 2021, when the connection from bothsides was done. Obtaining the following errors: X: -0.004 m; Y: -0.034 m; Z: -0.033 m. Achieving an accuracy substantiallyhigher than the expected values, either planimetry or altimetry.

References[1] L. Sanmiquel, M. Bascompta, J.M. Rossell, “Assessment of errors in the transmission of the orientation and cartographic
system from the surface to an underground mine,” Journal of the Southern African Institute of Mining and Metallurgy,
vol. 120, no. 2, pp. 139-148, 2020.
[2] R. David, F. Foote, J. Anderson, E. Mikhail, “Surveying. Theory and Practice (sixth ed.),” McGraw-Hill, 1981.
[3] S.C. Stiros, “Alignment and breakthrough errors in tunnelling,” Tunnelling and Underground Space Technology, vol.
24, pp. 236–244, 2009.
[4] N. Benecke, U. Kalz, “Ensuring tunnel navigation by cost-effective gyroscope control measurements,” Tunnelling andUnderground Space Technology, vol. 24, pp. 236-244, 2009.

MMME 114-1