Lean Mining, Productivity and Occupational Health and Safety: An Expert-Elicitation Study

The implementation of lean tools in the Canadian mining industry is still in its beginnings. To the best of our knowledge, published information and ar-ticles on this subject are scarce. Consequently, the impacts of using lean tools on productivity and workers’ health and safety in this field are still unclear and need more investigations to better integrate the technical aspects of lean with Occupational Health and Safety (OHS). Therefore, this study aims to provide insights about lean mining in Canada. The objective of this paper is to propose a preliminary road-map for lean implementation considering OHS concerns in Canadian underground gold-mining. To meet this objective, a set of lean tools (i.e. VSM, 5S, Kaïzen, TPM, SMED and LIC) as independent variable, and OHS indicators (i.e. “struck by an object” and “body reaction” risks) and an economic indicator (i.e. daily advance rate) as dependent variable were selected. An expert-elicitation study was conducted re-cruiting 7 experts from academia and practitioners active in the mining sector. Results show that the majority of experts agreed on a possible positive impact on a mine’s daily advance rate after implementing 5S and TPM, and a reduction of the risk rate of “struck by object” among workers by implementing Kaïzen.


Introduction
Lean manufacturing is originating from Toyota Motor Company. It was initially known as Toyota Production System (TPS) (Ohno, 1988) [1] and it started when employees participation. The Toyota management team then improved the TPS and introduced the lean manufacturing system to the world, a production system that helped them improve their productivity and increase their profits through systematic process waste removal (Shingo et al., 1989;Womack et al., 1990) [2] [3]. In the past three decades, many companies from different sectors have tried to implement lean management into their production platforms after witnessing the major success of lean at Toyota (Flynn et al., 2015;Bhamu et al., 2014) [4] [5]. To this effect, companies around the world and from various industrial sectors started using different tools to implement lean and eliminate or reduce seven stages of waste in their daily activities (Sternberg et al., 2012) [6]. Bhamu et al. (2014) [5] and Hodge et al. (2011) [7] summarize that tools such as

Literature Review: Lean Mining
There are plenty of publications on the results of lean tools in the manufacturing sector (Flynn et al., 2015) [4]. However, for the mining industry, there is little information and very few studies about lean implementation (Lööw, 2018; Hasle, 2014) [8] [9]. Sanchez et al. (2004) [10] mention that it might be possible to implement the principles of lean equally in every industry. On the other hand, Hattingh et al., (2010) [11] points out the different nature of the mining environment compared to the manufacturing sector and questions the possibility of successfully integrating lean tools in mining with the same approach as has been used in the manufacturing sector. In addition, Khaba et al. (2018) [12] point out that the level of lean awareness amongst miners could vary from one mine to another. Factors such as variability and uncertainty are known barriers in mining that can hinder the implementation of lean in this sector (Nadeau et al., 2015;Flynn et al., 2015) [13] [4]. Available literature addresses mainly the improvements in productivity once lean tools have been used ( [15]. Table 1 summarizes the available studies that examine the use of lean tools in the mining sector. These studies can be categorized as follows based on the implemented lean tools: • Lean Information Center (LIC): In conjunction with 5S, using LIC resulted in early stage performance improvement in an aluminum mine, cycle time reduction in a bauxite mine and cycle time enhancement in an underground copper mine (Dunstan et al., 2006) [16].
• VSM: Productivity improvement in a fluorspar mine, enhancement of process  [19]. • Kaïzen: In conjunction with other tools such as VSM and 5S, using Kaïzen resulted in project performance and productivity enhancement in a copper mine (Castillo et al., 2014) [14] and possible improvements in the miners' health and safety conditions (Vaněk et al., 2015) [20]. • TPM: Repair time reduction in a copper mine (Chlebus et al., 2015) [21].
It is important to mention that there are certain differences in the legislative, environmental and geological conditions in each country specified in Table 1.
Therefore, comparing these results may be difficult without considering these differences. Moreover, there are some drawbacks and limitations in the implementation of lean mining (Hines et al., 2018) [22]. There are different definitions of lean in the literature (Stone, 2012) [23]. Bhamu [24]. Consequently, this paper has chosen it as its definition of lean: "An integrated socio-technical system whose main objective is to eliminate waste by concurrently reducing or minimizing supplier, customer, and internal variability" (Shah & Ward, 2007: p. 791) [24]. Stahl et al., (2015) [25] argued that some companies are ignoring the actual concept of lean in a social sense and are using lean tools only for waste removal purposes and have not yet been integrated with the OHS aspects. To fill this gap, the objective of this paper is to develop a preliminary road-map to help integrate lean tools into mining industries considering their impacts on the overall health and safety of miners.

Research Method: Identifying Variables
As previously mentioned, information about the implementation of lean tools in mining regarding OHS issues is scarce in the literature (Nadeau et al., 2015) [13]. Therefore, to gain in-depth knowledge about this subject for this paper, a qualitative research approach was followed (Creswell, 2013;Fortin, 2010) [35] [36]. An expert elicitation study using semi-directed interviews was undertaken to discover any possible links between the integration of lean tools and the eco-  [40]. Therefore, these two indicators were selected as OHS-dependent variables. As for an economic indicator, increasing the rate of production is an important factor to consider in the mining field (Pareja, 2000) [41]. Taking into account the geological and environmental conditions in Canadian underground gold mines, productivity is tied with the daily advance rate for extracting ore (Pareja, 2000) [41].
Consequently, the advance rate per day was chosen as the economic dependent variable.

Data Gathering and Analysis Method
Holding a semi-directed interview with Canadian experts was deemed useful to [43] were interviewed for this project. These experts were chosen amongst active academia and practitioners in the mining sector. Obtained data from the interviews were converted to text and then categorized using an Excel spreadsheet. By using this software, the important keywords within the text (i.e. productivity, productive, performance, safety, injury, health, OHS, prevention, positive, impact, link, more studies, increase, decrease, improve, improvement, avoid, effective, efficient, reduction, reduce, lean tools, profitable, cost) were categorized and sorted and their patterns were compared with each other to find meaningful behaviours (Berg, 2001) [44]. The output results were interpreted in the last step, that is, the identified patterns were studied and the results were compared with the literature to draw a conclusion. Figure 1 shows the different steps of the methodology of this research.

Results
As mentioned above, a semi-directed questionnaire was distributed to the ex-  were also asked about their opinions regarding possible connections between the set of lean tools and each OHS and economic indicator. A summary of these results can be seen in Table 2.
A. Nemati et al. • It depends on the mine.
• 71% did not know if there was a link.
• 71% did not know if there was a link.
• It can increase the paper work.

5S
• 57% did not know if there was a link.
• It might be difficult to sort the mining supplies.
• 43% did not think there was a link.
• 43% believed that there is a link.
• It can increase productivity.

Kaizen
• 57% agreed that there is a link.
• Better understanding of tasks and responsibilities.
• 43% did not know if there was a link.
• 43% did not know if there was a link.
• 43% believed that there could be a positive link.

TPM
• 43% did not know if there was a link. • 43% did not know if there was a link. • 43% believed that there is no link.
• 57% agreed that there is a link.
• It can increase the daily advance rate.

SMED
• 57% did not know if there was a link. • 86% did not know if there was a link.
• 57% did not know if there was a link.

LIC
• 57% did not know if there is a link. • 57% did not know if there is a link.
• 43% did not know if there is a link.

VSM
For VSM, the majority of the experts did not think or were not sure whether there is a link between this lean tool and "struck by object" risks (57%), "body reaction" risks (71%) and "daily advance rate" (71%). This could indicate that more studies are required to assess the outcomes of using VSM on the OHS and productivity indicators for an underground mining environment.

Five S
As for 5S, 57% of the experts did not know if there is a connection between 5S and "struck by object" risks and 43% did not think there was a possible link between 5S and "body reaction" risks. On the other hand, the majority of the experts (43%) believe there is a connection between the "daily advance rate" and 5S. Improving productivity is a positive effect of using 5S in the mining industry from these experts' point of view. This means that, in the experts' perspective, implementing 5S elements in the workplace should improve the daily advance rate.

Kaizen
More than half of the experts (57%) agreed that a link exists between Kaizen and "body reaction" risks. Eventually, less than half of the experts (43%) responded that they do not know whether there is a link between this lean tool and the "daily advance rate" for Canadian underground gold mines. That being said, the same number of experts (43%) commented that there might be a positive link. These experts agreed that Kaizen could improve productivity and enhance efficiency through continuous improvement practices.

TPM
For this tool, the majority of the experts did not know if a link could be made between TPM and "struck by object" risks (43%). The results are divided in two groups as for "body reaction" risks. A first group of 43% did not know about a link while the other 43% mentioned that there is no link to be made between these two variables. The majority of the experts (57%) mentioned that there could be a link between TPM and productivity. According to these experts, increasing the "daily advance rate" and obtaining an uninterrupted production pace can be achieved by properly implementing TPM. This indicates that performing a regular maintenance according to the TPM guideline should improve the productivity of the underground mine.

SMED
Similar to VSM, the majority of the experts did not know if a connection could be made between SMED and "struck by object" risks (57%), "body reaction" risks (86%) and "daily advance rate" (57%). This could mean that the obtained results are inconclusive and that more studies are needed to investigate the outcome of using SMED on OHS and productivity indicators in the mining environment more thoroughly.

LIC
Again, similar to VSM and SMED, the majority of the experts did not know if there is a link between LIC and "struck by object" risks (57%), "body reaction" risks (57%) and the daily advance rate (43%). This could mean that an assessment of the outcomes of implementing SMED on OHS and productivity indicators in the mining environment requires more study.
By combining all the statistical results related to each variable in this study,   it can be seen that about 45% of the experts' answers were that they did not know whether there is a connection between implementing lean and the economic indicator for mining ( Figure 5(b)). An overview of the obtained results of this research is presented in Figure 6. This figure shows the final results of this study and generates a preliminary road-map to help implement lean mining and address the objective of this research.

Limitations and Biases
Initially, a total of 10 experts were recruited. 7 experts completed the questionnaire. The scientific community in lean mining in Canada is limited. The results of this research are limited to gold mining. Moreover, having such a small sample size prevents a generalization of the final results of this expert-elicitation study (Yin, 2013) [47]. On the other hand, for a study with little or no earlier background information, the qualitative expert-elicitation method provides the  [45]. This method is especially useful when not much experience about the studied subject has been documented a condition that applies to this study as well.
One of the possible biases of this research could be due to each expert's mindset about lean. Each expert might have their own perspective about lean, which could differ from that of the other experts. As mentioned in the results section, the majority of the experts described lean as an effective way to minimize loss of time, reduce costs and optimize production. This indicates that most of them see lean as a waste management tool to improve efficiency. This is in accordance with what was established as the definition of lean in this paper (Shah & Ward, 2007) [24]. Another bias of this study is that almost none of the experts had any previous formal lean-related training. Some experts obtained their information about lean through readings and waste-elimination practices used by their mining companies, which could be considered as a form of training. However, this could have an impact on the presented results.

Literature Comparison
By comparing the findings of this study (  [20] in coal mining. Decreasing the rate of the risk of being struck by an object after implementing Kaizen was one of this research's findings.

Future Studies
This study was an attempt to make an initial foray for further studies by creating a preliminary road-map to help implement lean in the mining sector regarding workers' health and safety. Future studies can focus on more field work observations and case studies to investigate lean mining more in depth. Knowing that results of this study were obtained for the underground gold-mining sector, other mining sectors should be involved in future studies as well, to create a more comprehensive and conclusive road-map regarding the connection between lean mining, OHS and productivity in Canadian mines.
One of the main objectives of this study was to investigate the connection between implementing lean and OHS and productivity in the mining environment.

A. Nemati et al. American Journal of Industrial and Business Management
The final results showed that some lean tools can be effective in enhancing OHS and mining productivity. However, the impact of lean mining as a whole (implementing a set of lean tools) on OHS and productivity is still unknown (Fig.   5). The findings of this study are still inconclusive regarding this matter. This highlights the fact that lean in mining is still emerging in Canada and more research is required to reach more tangible conclusions.

Conclusion
Unlike the manufacturing sector, there are little information and studies about the outcome of lean integration in the other sectors. Moreover, implementing lean into Canadian mining sector is still emerging. To the best of our knowledge, very little information in the literature exists about the impact of lean implementation on mining productivity and OHS. The published information is even rarer regarding the Canadian mining sector. By conducting an expert-elicitation study with 7 Canadian experts, a preliminary road-map was created to show the possible links between lean mining and productivity and workers' safety in Canadian underground gold mining. This map can help to provide more in-depth knowledge about which lean tools would be better to start with for future case studies, to investigate more about the impacts of lean mining on OHS and productivity. Results from both the literature and this study show that tools such as 5S, TPM and Kaizen may potentially have positive impacts on mining productivity and OHS. This paper showed that using 5S and TPM can increase the daily advance rate and Kaizen can be useful in reducing the rate of "struck by an object" risks among workers in underground gold mines in Canada. Although this study did not reach a conclusion about the outcome of implementing lean (as a set of tools) on OHS and productivity, it does, however, pave the way for further research about Canadian lean mining.