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Modern mine productivity places a very strong focus on achieving high levels of control over fragmentation, wall control (damage to excavation limits) and environmental impact. The introduction and extensive use of electronic initiation heightens the focus of each one of these blasting outcomes, though systems to permit optimisation are not readily or widely available, and are seldom used in any routine manner in the mining industry. Seed wave modelling, in conjunction with electronic initiation, enables blasting engineers to identify optimum timing configurations for any type of blast, with respect to each of the three mentioned blasting outcomes. Fragmentation, either in the body of the blast or in the stemming zone of blasts, can be increased substantially by optimising timing from the point of view of maximising induced stresses within the rock mass, enabling quantification of a fragmentation index for specific vertical bench sections. Damage, either in the bench batter behind a limits blast, or in the underlying berm, can similarly be minimised by careful delay timing, often more effectively than by costly reduction of blasthole diameter, enabling definition of a Probability of Damage curve. Environmental vibration impacts, either in the medium-field as an impact on vibration-sensitive slopes or mine sectors, or in the far-field as an impact on nearby occupied structures, can also be minimised by careful selection of delay timing. This paper presents the use of seed wave modelling as an everyday tool to enable blasting engineers to make engineering-based decisions regarding the delay timing which will bring maximum control over these blasting impacts.

The topic of blasting near pit walls is one that invokes mixed reactions from different mining departments. For many mine operations and mine scheduling departments, it often represents a significant disruption to efficient work flow, while to geotechnical departments it represents a critical component in the task of delivering safe and competent pit walls and compliance with pit slope design. Many different approaches exist to help achieve the desired end result of safe pit walls and compliance with pit slope design, suggesting that there is no single best-solution. This paper explores some of the contemporary paradigms which strive to achieve the desired end result, with a particular focus on presenting a thought process aimed at trying to avoid unnecessary and ineffective restrictions on mining practices and wall control blasting. Practices such as reduced blasthole diameter, pre-splitting, trim blasting, initiation sequences and systems and reduced blast size will be explored using modelling based upon field measurements. How well do we understand the impacts of blasting on pit wall integrity and pit slope stability? While there is no single design that suits all mining applications, there is a single thought process that should lead each mine to quite quickly decide on the most appropriate solutions for areas of different sensitivity regarding slope stability.