Abstract: The invention provides a method and apparatus for electronically testing the safety of sources of energy such as electrical circuits, in explosive atmospheres such as high risk mining situations, using an electronic spark tester (EST) in place of the known mechanical spark test apparatus (STA). The EST typically uses an analogue subsystem (5) and a digital subsystem (6) connected by a digital to analogue converter (7) and an analogue to digital connector (8) to apply a simulated spark load to the energy source and measure the time varying current response to that load.

Abstract: In particular embodiments of the technology, the bulk density of the payload in the bucket of a large electric dragline is measured during the carry phase of dragline operation by scanning the loaded bucket using a boom mounted scanner to provide data relating to the volume of the loaded bucket. Suitable methods can further include calculating the volume enclosed by the surface of the payload and the known base and sides of the bucket to give payload volume, and dividing the payload volume into payload weight data derived from rope length and motor current data to give the payload bulk density. Methods of screening data points originating from surfaces other than the bucket and payload, and methods of dealing with bucket ope and sway are also described and claimed.

Abstract: In particular embodiments of the technology, the bulk density of the payload in the bucket of a large electric dragline is measured during the carry phase of dragline operation by scanning the loaded bucket using a boom mounted scanner to provide data relating to the volume of the loaded bucket. Suitable methods can further include calculating the volume enclosed by the surface of the payload and the known base and sides of the bucket to give payload volume, and dividing the payload volume into payload weight data derived from rope length and motor current data to give the payload bulk density. Methods of screening data points originating from surfaces other than the bucket and payload, and methods of dealing with bucket ope and sway are also described and claimed.