JKBench

DOWNHOLE DELAY mode

                                  insert downhole delays in blast holes - detonators, connectors, primers

  downhole delay parameters

  insert delay in a single hole

  insert delays in all holes

  insert delays in marked holes only

  insert delays in unmarked holes only

  query - display information about a delay

Edit Menu

Delete Downhole Delays

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Downhole delays are inserted into blast holes to detonate decks of explosives. A blast hole can contain more than one delay. At least one delay must be inserted in every group of explosive decks: if two or more adjoining decks are explosive materials, then only one delay located somewhere within the decks is required; however, if the explosive decks are separated by a non-explosive material, then a delay is required in each deck.

The main features of this mode are:

• insert detonators, connectors and primers
• insert at distance from toe or collar
• properties stored with design

Connectors are used to join a downhole detonator to the surface delay at the collar. The burn rate of the connector is taken into account when calculating the actual detonation time of the delay during detonation simulation. A primer can be included with the downhole delay, but it has no effect on the performance of the blast hole.

If the visibility option for downhole delays is turned on, the topmost delay is represented as a coloured triangle inside the blast hole.

      Downhole Delay Parameters

Selecting a Delay

The Downhole Delays dialog is used to select a detonator, connector and primer and the position of the delay in the hole. Normally, items are selected from the JKBench series, but the display can be limited to a sub-set of created items. Click [Show Details] to display the properties of the selected item.

Distance

Two options are available to insert the delay at a position in a hole. Enter a distance for either option. If a [from collar] is selected, the delay will be placed at that depth down the hole; if [from toe] is selected, the delay will be placed at that distance measured up from the bottom of the hole. The final length of the connector is calculated as the depth of the delay from the collar. A set of conditions apply to the calculation of the depth:

1. if the distance is greater than the length of the hole, the depth will be equal to the hole length
2. if the distance is greater than the fixed length of the connector, the depth will be the length of the connector
3. if [from toe] is selected and the holes are different lengths, then the depth of the delays will also vary in each hole

      Insert Delay in a Single Hole

To insert the selected detonator, connector and primer in a single hole, place the cursor near the hole and click.

      Insert Delay in All Holes

To insert the selected detonator, connector and primer in all holes, place the cursor anywhere in the design area and click.

      Insert Delay in Marked Holes Only

To insert the selected detonator, connector and primer in marked holes, ensure that the holes are marked, then place the cursor anywhere in the design area and click.

      Insert Delay in Unmarked Holes Only

To insert the selected detonator, connector and primer in unmarked holes, ensure that the holes are unmarked, then place the cursor anywhere in the design area and click.

      Query - display information about a deck

Displays details of the data for the first delay in the nearest hole to the cursor. The hole is highlighted. To display the next delay in the same hole, click with the cursor on the hole, or click in the hole diagram. To select a different hole, move the cursor. For more information, go to Design Area: Query.

   Edit menu: Delete Downhole Delays in All / Marked / Unmarked Holes

Delete all downhole delays from the design.

To delete a single delay, place the cursor near the hole and press [Backspace]. The topmost delay in the hole (closest to the collar) is removed. Repeat to remove the next delay in the same hole

Overview

JKBench is a program for the design and basic analysis of blasts in open cut mines. It allows the user to layout a blast design consisting of blast holes, decks, downhole and surface delays and connections, and then to run a detonation simulation. The design can be further described by strings and polygons. Basic analyses of volume, tonnage, powder factor, component and total costs can be calculated for the design.

Although the design is created in 2D plan, all data is stored with full 3D coordinates (east, north, level) in a Microsoft Access database. Added to this are object details (such as hole dip, bearing, diameter, length, burden, spacing), properties of explosives, detonators, primers and connectors, plus timing information.

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Program Features:

A blast design is divided into five component options, created in the various modes in the program. Each mode has specific tools and functions, with several global editing tools and reporting, query, input and output functions.

Area mode (Line/Polygon Creation) draw and edit strings and polygons set text labels on the design import strings and polygons cut/copy/paste strings and text labels
Drill mode (Hole Creation) hole properties and pattern parameters drill single holes and patterns (square, staggered) import holes from text file cut/copy/paste holes and attached data
Load mode (Material Loading) load multiple decks of materials load by length, mass, depth from collar or percentage of hole length explosives and non-explosives (stemming, air-deck, water, etc) properties stored with design
Down Hole Delays mode (Downhole Delay Sequencing) insert detonators, primers and connectors insert at distance from toe or collar properties stored with design
Surface Delays mode (Surface Delay Sequencing) define detonators and connectors connect any two holes or a line of holes inter-hole, inter-row, uni- and bi-directional properties stored with design
Detonate mode (Detonation Simulation) simulate the detonation sequence on screen continuous and step display show separation of initiation and detonation fronts display detonation times for all components all timing results saved in design database
Analysis tools contour of first detonation times for holes chart of maximum instantaneous charge with calculation of PPV and airblast calculate powder and energy factors based on defined volume or design parameters calculate totals for design components: count, quantity, mass, cost copy design data to external application (e.g. spreadsheet) copy results to external application or save to file
General tools cut, copy and paste data internally or externally import strings and hole layouts from text files zoom in/out or set scale of design area query details on holes, decks, delays, strings, etc print design to scale save screen appearance and design parameters select display of metric or imperial units data saved in Microsoft Access databases is available to other applications

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