Cardu, M., & Seccatore, J. (2016). Quantifying the difficulty of tunnelling by drilling and blasting. Tunn. Undergr. Space Technol., 60, 178–182.
Abstract: This study deals with industrial trends in tunnelling by drill and blast (D&B). We perform a statistical analysis of accumulated experience from the 1950s to the modern day to provide advice for proper project management in tunnel driving. The basis of the study is a wide database of tunnel blast schemes. This database is made of excavation parameters, and considers two main families of blasts: with parallel hole cuts and with inclined hole cuts. Such parameters are analysed by means of statistical regression. Correlations are shown. We present a general curve of correlation between tunnel sections and specific drilling and specific explosive consumption. We show how pull efficiency cannot be correlated to a single parameter, and how tunnelling by D&B needs to be treated as a complex system. Finally, we propose a method for quantifying and classifying the difficulty of tunnelling. The deviation of specific drilling (SD) from industrial average trend is used as an indicator of difficulty: easier when SD is lower than average, and more difficult when SD is higher than average. We show how such deviation can be preliminarily associated with lithotypes. This provides to designers and cost estimators a tool of a first approximation for D&B cost prediction at the pre-feasability and feasibility stages of a tunnelling project. (C) 2016 Elsevier Ltd. All rights reserved.
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Cardu, M., Godio, A., Oggeri, C., & Seccatore, J. (2022). The influence of rock mass fracturing on splitting and contour blasts. Geomech. Geoengin., 17(3), 822–833.
Abstract: Splitting and contour blasting are aimed to achieve suitable profiles by cutting along a surface, while common blasting is intended to detach and to fragment relevant rock volumes by increasing the fracturing state. These techniques are adopted in both underground works (tunnels, caverns, quarries) and also for surface excavations (quarries, mines, rock slopes engineering). Contour blasts are widely used techniques in mining and civil engineering to enhance performance while maintaining the safety of personnel and infrastructure. Splitting blasts are mainly used in dimension stone mining to obtain intact blocks of valuable ornamental stone. The parameters of controlled blasting (geometry, charge, blast agent) require an accurate selection using optimised blasting patterns and explosive properties; most of the proposed methods are limited and unsatisfactory due to insufficient consideration of rock mass properties. A quick but effective comparison and analysis of the different characteristics of the rock mass and its heterogeneities is presented, as it indicates a better strategy to determine a tailored blasting design for a given site, thus significantly improving the contour blasting quality.
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Cheng, Y. C., Nakajima, K., Nansai, K., Seccatore, J., Veiga, M. M., & Takaoka, M. (2022). Examining the inconsistency of mercury flow in post-Minamata Convention global trade concerning artisanal and small-scale gold mining activity. Resour. Conserv. Recycl., 185, 106461.
Abstract: In 2017, the Minamata Convention (MC) on mercury (Hg) control entered into force. However, whether the MC is effective and how it reshapes the global Hg flow remain unclear. In this study, we established a method to detect inconsistencies in data on global Hg trade, and calculated the gap between the demand and supply of Hg to the artisanal and small-scale gold mining (ASGM) sector (i.e., the largest source of Hg emissions globally) in 39 countries across four regions. According to our results, inconsistencies in statistical data concerning Hg for ASGM activities exist in both Africa and Central and South America. Asia showed a considerably lower amount of Hg applied to ASGM than apparent Hg consumption; nevertheless, the largest consumer of Hg was Asia, predomi-nantly China and India. Many countries in which ASGM is conducted are already MC parties; however, only few submitted their national action plans (NAPs) or have established/enforced specific laws to curb Hg use in ASGM. Analysis of Hg-related trade information suggests that in 2017, the trade of metallic Hg disappeared in some African and Central and South American countries, but new trade flows of goods with higher Hg content emerged. The method established in this study can support the search for countries implementing ASGM with hidden Hg use and flows, thereby contributing to the planning of further Hg control regulations. To enforce sound Hg management, the submission of NAPs should also be promoted in addition to the expansion of MC parties.
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Cheng, Y. C., Watari, T., Seccatore, J., Nakajima, K., Nansai, K., & Takaoka, M. (2023). A review of gold production, mercury consumption, and emission in artisanal and small-scale gold mining (ASGM). Resour. Policy, 81, 103370.
Abstract: Artisanal and small-scale gold mining (ASGM) is one of the largest sources of Hg emissions and is critical for addressing the Hg problem. Due to scarce and punctual statistics provided by governments and agencies, there is almost no accurate data on ASGM production, Hg use, and emissions. In this study, we surveyed different ap-proaches to estimate ASGM production and collected data from different sources, including academic papers and technical reports. Globally, 380-870 tonnes of gold is produced by ASGM each year, with a median value of 520 tonnes. The Hg use in the ASGM sector was estimated to be 640-1000 tonnes each year, with a median value of 892 tonnes. Consequently, 248-838 tonnes of Hg are emitted from the ASGM sector each year, with a median value of 615 tonnes. However, significant discrepancies were found in the data calculated using different ap-proaches, particularly in countries where the estimates were large, such as China. To obtain a more accurate picture of global ASGM activities, a general estimation approach combining specific studies of dominant coun-tries is necessary. For better management of ASGM in the future, developing a solid baseline and comprehensive future projection scenarios and establishing international collaboration to construct guidance on ASGM are recommended.
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Di Lorenzo, A., Pasqua, A., Cardu, M., Godio, A., & Seccatore, J. (2019). Simplified methods of geomechanical analysis for small-scale underground mining. In 14th International Congress on Rock Mechanics and Rock Engineering.
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Dragano, M. A., Seccatore, J., Cardu, M., Marin, T., & Bettencourt, J. (2019). Influence of blasting charges and delays on the energy consumption of mechanical crushing. REM, 72(2).
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Espinoza, C., Seccatore, J., & Herrera, M. (2020). Chilean artisanal mining: a gambling scenario. REM, 73(2).
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Godio, A., & Seccatore, J. (2019). Measuring the Reduction of the Confinement along the Evolution of a Burn Cut. Appl. Sci.-Basel, 9(23), 17 pp.
Abstract: We provide an analysis of a tunnel opening cut in a tunnel face. In particular, we focus on the effect of a “burn cut,” which is a typical parallel hole cut. As the evolution of the opening consists of an increase in the volume of the cut prism and the consequent reduction of confinement of the holes along the initiation sequence, we analyze such an evolution using photographic documentation, as well as evaluating the reduction of confinement by measuring the energy transferred from the explosive charge to the rock mass. The energy was estimated by monitoring and analyzing the vibrations induced by the blasting at three different points. We adopted low-cost shock sensors for monitoring the effect of the detonation times at short distance from the blast (about 10 m). The results show an evident reduction of the shock transfer to the rock mass (i.e., a reduction of confinement) with the increase of the cavity opening. Nevertheless, when only the response of the piezometric sensors was considered, a disparity in behavior among the sensors was noted. On the other hand, when the sensor response was integrated over time, the behavior of all sensors normalized, showing the need to focus both on the oscillation and the duration to properly address the shock effect.
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Seccatore, J. (2019). A review of the benefits for comminution circuits offered by rock blasting. REM, 72(1).
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Seccatore, J., & de Theije, M. (2017). Socio-technical study of small-scale gold mining in Suriname. J. Clean Prod., 144, 107–119.
Abstract: Small-scale gold mining is Suriname's main economic sector, producing about two thirds of the nation's gold. Despite this, the sector is only very loosely regulated and most small-scale mining activities are informal. Surinamese miners are only a minority: the majority are Brazilian migrants, who have no right to the land and therefore have to pay a percentage of their production for land use. This study reports the findings of a field mission to small-scale mines in the region of Brokopondo reservoir. We document the technical aspects of small-scale gold mining in Suriname and contextualize this technology to social issues to identify links with cultural, political and sociological factors. Our findings show that informality and insecurity lead to a mine management culture that applies short-term solutions, such as cheap but polluting and inefficient technologies, and fails to produce stable, long-term mining conditions for clean, efficient technology and secure business planning. We conclude that the social context of the mining economy in Suriname strongly interacts with the technologies employed. (C) 2016 Elsevier Ltd. All rights reserved.
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Seccatore, J., Gonzalez, P., & Herrera, M. (2020). Peculiarities of drilling and blasting in underground small-scale mines. REM, 73(3).
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