The Details of the Major Modifications of the Processing Plant

This section describes the major changes to the original design of the TM processing plant. The section starts from the front end of the plant (ROM Pad) to the tailings section of TM processing plant.

2.5.2.1 Primary Feed Point of TM Processing Plant

The original design of the TM processing plant stored the run-of-mine ore in an open area (ROM Pad) located in front of the primary crusher. Due to the rainfall throughout the year in Twangiza area, the ore was exposed to the rain. This exposure contributed to the ore moisture that impacted badly on the crushing section. The Mineral Sizer (primary crusher) as well as other equipments downstream were always chocking during the rainy season. The clayey nature of the Twangiza ore made the situation worse.

The TM project decided therefore to cover the ROM pad with a roofing structure. The construction of that cover was completed in the second quarter of 2014. The completion of the ROM pad roof allowed dry storage of up to 25,000 tonnes of a mixture of both Rom ore and pre-crushed and pre-screened ore products from the re-handling section of the pit. The idea behind this roofing was to protect the stockpiled ore from the rain and thereby to reduce the moisture content of the ore.

Historically, ore processed through the plant exhibits significant changes in overall moisture content from dry to wet season. Wet sticky clay ore is extremely difficult to process in the crushing section of the process plant. Controlling the moisture content of ore, especially ores with high fines or clay content, minimizes the effect of changes in the viscosity of the ore. Drier high clay content ore has better flow and processing characteristics than ore that has been exposed to rainfall.

27 2.5.2.2 Secondary Feed Point of the Plant

During the implementation of the expansion project it became evident that overall plant availability and utilization could be enhanced by feeding crushed and screened ore into the plant via a secondary feed point. Originally a small feed hopper was installed over the scrubber screen discharge conveyor (23-CVR-01) in the crushing area to facilitate the loading of alluvial ore mined from below the TMF into the plant. This allowed ore to be fed directly to the grinding circuit via the mill feed bin, bypassing the front end altogether.

This concept was developed further during 2014 through the installation of an additional feed conveyor located adjacent to the mill feed been conveyor (23-CVR-08). The use of available mobile crushing and screening equipment to provide -25 mm ore to the grinding circuit has now become permanent operating practice providing supplementary feed on an hourly basis as required to keep the grinding circuit operating effectively while the front end of the plant is shutdown.

2.5.2.3 Plant Crushing and Screening Section

A more powerful crusher, the ALP 625 series replaced the existing primary MMD Mineral Sizer. This new primary crusher had a double drive unit, allowing for an increase in throughput up to 300 wet tonnes per hour. Operating experience with the new ALP Mineral Sizer quickly highlighted shortcomings in the tooth design and tooth replacement strategy, particularly when processing mudstone ore during the wet season. To address that teeth shortcoming, the tooth change out regime on the new ALP Mineral Sizer was radically changed from the design “even” tooth pattern to an

“uneven” one increasing the nip angle between the teeth significantly thereby improving throughput and reducing down time and maintenance costs.

The existing apron feeder drive and primary conveyor feed conveyor [21-CVR-01] drive units were found to be adequate and did not need upgrading as had been planned to

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achieve the throughput of 1.7 Mtpa. The speed of the apron feeder feeding the ALP Mineral Sizer was capped at 72% to eliminate overloading of the primary feed conveyor.

The conveyor belt width was increased from 750 mm to 800 mm and the installation of additional training idlers on the carry and return portions of the belt greatly increased belt operating time and reduced spillage. The scrubber fines pumps were upgraded with new 75 kW motors and upgraded VSD’s (variable speed drives).

A single 315mm OD pipeline with smooth long radius bends was installed to replace the original twin 250mm lines with sharp 90 degree elbows that were prone to sanding out.

The original Zenith HPC220, 220 kW Secondary Cone Crusher and the Zenith HPF220, 220 kW Tertiary cone crusher, were removed and replaced with more robust Secondary and Tertiary FLSmidth Raptor XL300 Crushers. Installation was completed in June 2013.

2.5.2.4 The Upgrading of the Feed Weightometers

At the higher feed tonnages the scrubber feed weightometer and the Mill no. 1 feed weightometer were out of range which potentially introduced significant metallurgical accounting errors in terms of measurement of the feed tonnage. Both weightometers were changed to larger units.

2.5.2.5 Milling Section

The implementation of the expansion to 1.7 Mtpa was incremental in nature and it was realized that an upgrade to the existing grinding circuit was not required at the time but recognized that it would be needed for any further expansion. However a number of minor changes were made to the installed equipment in the grinding circuit to enhance circuit performance and to effectively operate at 1.7 Mtpa.

The trommel panels on both No.1 and No.2 ball mill were changed from 10 mm polyurethane panels to 10 mm wire screens to increase the effective open area and

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screening efficiency. The cyclone feed pipelines were extensively replaced with durable rubber mining hose with smooth long radius elbows for improved pumping efficiency and longer service life. A fourth cyclone was added to the cyclopack increasing the number available from three to four. An additional 9m² Linear Trash Screen, required to handle the increase in flow rate with the planned tonnage increase was ordered and installed in parallel with the current operating Linear Trash Screen. The existing Linear Trash Screen would be relocated to feed the new #2 CIL Tank to be constructed, and the CIL would be operated as two parallel trains.

2.5.2.6 Carbon-In-Leach (CIL) Section

The construction of four new, 412m³ CIL Tanks (same size as existing # 1 and 2 CIL Tanks) was completed in September 2013. The new tanks were constructed at the head of the existing CIL train, in order to increase the residence time at the original tonnage and enhance the residence time with the future increase in tonnage. Four new Kemix agitators were installed in the new CIL tanks. Ten complete Kemix MPS700(P) mechanically swept interstage screens were also installed throughout the CIL circuit. All the screens would have 800 μm baskets.

The existing static, air swept, wedge wire screens in CIL tanks #8 thru 13 were prone to choking and were replaced with mechanically swept Kemix MPS700(P) screens, the same as installed in the first eight CIL tanks. All screens would be fitted with 800 μm screens which would allow the tanks to be operated at higher pulp densities than before, thereby allowing better mixing of the carbon in pulp, improved adsorption efficiencies, reduced dissolved gold loses, savings in reagents, increased residence time and improved performance of the CIL in general. The airlifts for carbon transfer in CIL tanks #8 through 13 were replaced with vertical spindle pumps, thereby eliminating the excessive use of blower air, which was better utilized for agitation and leaching in the CIL. A total of ten FLSmidth Krebs 4x4 1.8L vertical carbon transfer pumps were installed throughout the CIL circuit.

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Two used (110 operating hours) high capacity Atlas Copco ZE4 200kW 3.5bar blowers were installed and tied into the existing CIL air system to enable oxygen levels in the CIL to be increased, thereby improving leach kinetics and overall recoveries.

A second tower crane (used) was installed for construction and servicing of the new CIL tanks. This crane would be positioned so as to enable it to also be utilized to service the milling and cyclone area as well.

2.5.2.7 Acid Wash-Elution-Regeneration of Loaded Carbon

The original vertical carbon regeneration kiln was removed to make room for the new Kemix 300 kg/hour diesel fired horizontal regeneration kiln. A new (second) elution system, complete with horizontal regeneration kiln was installed and commissioned in August 2014 and operated in parallel with the existing carbon treatment system. This allowed for more efficient and more complete stripping of gold from the carbon, ensuring all stripped carbon was regenerated before it was returned to the CIL circuit, thereby improving recoveries and maximizing gold production.

2.6.2.8 Electro-winning and Smelting

The new elution system included two complete electro-winning cells, gold sludge recovery system, calcine oven, smelting furnace, gold scale, doré handling tools, a bullion safe, work bench and associated fume hoods and extraction fans.

2.6 Conclusion

The literature reviewed provides the current knowledge that constitutes the foundation of this research project. This consisted of four sections. The first section reviewed the different types of mining projects, and more especially in the Congolese context. The second section reviewed project management as well as changes that occurred during the life cycle of projects with their different approaches and goals. The third section addressed the impact evaluation of projects; its definitions, evolution over time, and the

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best practices to conduct evaluation. The last section reviewed the TMOEP by depicting the changes that affected the original TM processing plant design and also the goals pursued by this project under scrutiny.

In the next chapter, I provide an in-depth definition of relevant terminology, review models that support the selected methodology, and consider the research methods used to collect the data for this study. In addition, chapter three presents a discussion relating to the data analysis techniques used to interpret the data gathered.

32 CHAPTER 3 RESEARCH METHODOLOGY 3.1 Introduction

When expressing the aims and purposes of research, it is usually necessary to articulate the broad methodology that will be employed (Oliver, 2010). The purpose of a scientific research is to discover laws and postulate theories that can explain natural or social phenomena, or in other words, scientific research builds scientific knowledge (Bhattacherjee, 2012). Scientific research operates at both empirical and theoretical level. The theoretical level mainly develops abstract concepts that explain natural or social phenomenon, and establishes the relationships between those concepts. The empirical level focuses on testing the theoretical concepts and relationships in order to acknowledge whether or not the researchers’ observation reflect the reality, with the ultimate goal of building better theories (Bhattacherjee, 2012).

As stressed by O'Learly (2014) the design and methods of a scientific research consist of a logical and rhythmic approach that researchers need not only to become familiar with, but also to be able to apply with some level of competence and confidence.

Moreover, whether the research strategy is quantitative or qualitative, the researchers must describe the generic and procedural approach they use. By generic, researchers need to identify the suitable research methods (case study, ethnography, survey, etc).

Whereas the procedural approach entails the researchers to describe the specific steps taken to carry out their research strategy (Beraki, 2014).

According to O'leary (2014), research methodology deals with the theoretical background of the research by providing both the strategies and grounding for the conduct of the study. The data collected can be primary or secondary depending on whether data are new information gathered or not. In that sense, a research methodology serves to specify the collection of certain data and not others, the type of data to gather, and the kind of analysis required to examine and interpret those data.

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The primary goal of this study was to assess the impact of the TMOEP on selected gold mine in the DRC. This chapter presents the methodology employed in order to answer the research questions. The chapter comprises four sections. The first two sections detail the research design and the methods used to collect data. These details include the research design and the methods used to collect data as well as the rationale behind the choice of each specific approach leading to answer clearly to the research questions.

3.2 Methodological Design

The methodological design aims to develop a plan that allows the researcher to answer the well-articulated research questions, or else to validate the skilfully constructed hypothesis (O'Learly, 2014). This author views methodological design as plans for conducting research projects that include both the research methods and the methodology. The research methods are the micro-level techniques that help the researcher to collect data while the methodology is a macro-level framework that guides the researcher during the research process. In short, methodologies provide researchers with legitimization for knowledge production.

In order to understand the research methodology appropriate to address the research questions, researchers should review the different methodologies that exist in the literature. The literature distinguishes two main types of research methodologies.

The first type classifies research methodologies in term of the paradigms or traditions on which they are built up. Paradigmatically, research methodologies follow quantitative, qualitative, or else mixed research approaches (O'leary, 2014). The qualitative approach is very attractive as it helps researchers to gain a deeper understanding of the topic (Lunenburg & Irby, 2008). A qualitative research examines people’s words, actions, and records (Lunenburg & Irby, 2008). Therefore, the assumptions of a qualitative research are paradigmatically interpretivism, constructivism and subjectivism (O'Learly, 2014).

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Quantitative research on the other hand is usually labelled as an objective positivist search for singular truths that relies on hypotheses, variables, and statistics on generally large scale sample but without much depth (O'Learly, 2014). A quantitative research approach investigates such words, actions, and records at a mathematically significant level, thus quantifying the results of observations (Lunenburg & Irby, 2008). A mixed research approach engages both quantitative and qualitative research design and uses both probability and purposeful sampling (Lunenburg & Irby, 2008).

It’s important to note that quantitative and qualitative are two of the most confusing words in method language (O'Learly, 2014). In fact, these terms imply that designs that sit under the quantitative banner simply dismiss ‘words’, while those designs that sit under the qualitative banner do not have the time or space to deal with ‘numbers’. This is simply untrue. After all, isn’t quantitative data simply a coding system for qualitative concepts? And to think that you need to avoid counting or tallying in a qualitative study is ludicrous (O'Learly, 2014).

The second type depicts research methodologies by the purpose or goals of the research. In this type, O'Learly (2014) claims that research generates knowledge in order to build a broader understanding of the world (pure research), pave the way for change (applied or evaluative research), action change within an organization (action research), or in order to expose and change the dominant system (critical/radical ethnography).

This study evaluates an initiative launched to address process challenges. It strives to understand whether the initiative or project implemented was a successful endeavour or not. Moreover, this study analyzes whether the TM’s endeavour did what it was supposed to do or not. In that sense, the focus is to acknowledge whether the TM’s project made some contributions towards positive change. Based on these research questions, it’s clear that this paper follows an evaluative purpose as it reviews whether the project launched by TM has been able to alleviate process limitations or problems.

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According to O'Learly (2014) an evaluation research attempts to determine the value of some initiatives. In addition, evaluative research identifies an initiative’s consequences as well as opportunities for modification and improvement (O'leary, 2014). Furthermore, O'Learly (2014) asserts that the need for evaluation research is ever increasing as it’s actually a key strategy for supplying decision makers with the data they need for rational, informed, evidence-based decision making.

Evaluative studies basically attempt to determine whether an initiative should be continued as is, modified, expanded, or scrapped, and do this by asking two types of questions. The first related to outcomes where the research attempts to find out whether a particular initiative met its planned objectives. The second type of question deals with the initiative process. Here the research assesses how successful is an initiative’s implementation and tries to find ways to improve it.

In this study, the first type of evaluation research question interests the research.

Indeed, the research questions of this study attempt to address whether or not the objectives of TMOEP were met. The researcher strives to evaluate the outcomes of TMOEP. Basically, this paper simply tries to assess the effectiveness of implementing TMOEP by acknowledging whether the objectives or goals of TMOEP were met or not.

This type of evaluation research is called summative or outcome evaluation research as opposed to formative or process evaluation research (O'Learly, 2014).

The results of summative evaluations serve to inform decision makers to support, continue, terminate, expand or reduce a specific program or project. Although the results of summative evaluation are often case-specific, findings can be of interest to any number of stakeholder groups and, depending on the nature of the change intervention, might be of interest to the wider population as well.

36 3.3 Rationale for Single Case Study Method

Yin (2014) believes that case study is an appropriate method for conducting the evaluation of a program. The use of case study research in doing evaluations emanates from the need to gain an in-depth and close-up examination of a case in its real world context (Yin, 2014). Case studies are specific explorations of individuals, but also such investigations can be on groups, cohorts, cultures, organizations, communities, or programs (Lunenburg & Irby, 2008).

The origin of case study as a research design approach can be tracked back to the beginning of 20^th Century. Indeed, Strach & Everett (2008) in their research on case study found that this research design approach first appeared in literature as early as the 1930s.

Yin (2014), one of the well-known researchers in case study, defines case study as an

“empirical inquiry that investigates a contemporary phenomenon in depth and within its real-life context, especially when the boundaries between phenomenon and context are not clearly evident.” From this definition, it’s clear that a case study helps researchers to gain specific insight into a modern or current phenomenon which is occuring in its real-life setting. Case study research offers researchers the possibility to investigate a current pheomenon in context.

Another interesting point relates to the nature or the extent of a case. In an attempt to clarify the nature of a case, Yin (2014) notes that the term case refers to an entity, an event, an individual or even a unit of analysis. By there, one could deduce that case study doesn’t deal with the entire organization, but people only. Besides, case study doesn’t intend to study the whole organization; rather it intends to focus on a particular issue (Baharein & Noor, 2008).

According to Yin (2014), a case study research design should be considered when:

• The study strives to answer “how” or “why” questions;

• The researcher can’t manipulate the events under study;

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• The focus is on contemporary phenomenon with a real-life context.

• The focus is on contemporary phenomenon with a real-life context.