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CITY OF LATHROP 2. The drilling operations shall be conducted using equipment that is adequate to reach the depth and perform the evaluations specified in the Technical Provisions. If, in the opinion of the Engineer, the Contractor's equipment is not capable of satisfactorily performing the specified work, the Contractor, at his/her own expense, shall substitute equipment satisfactory to the Engineer. 3.The Contractor shall take all measures necessary to protect the top portions of the test hole from caving or raveling. 4.The Contractor shall keep records providing the following information: a)A record of construction activities for each shift. b) A time drilling log of the test hole recording the time (in minutes) required to drill down each section of drill pipe. c)A log of drilling bit types and depths of changes. d) Record of drilling fluid properties at 4-hour intervals during drilling operations. The record shall show drilling fluid weights, Marsh Funnel viscosity,sand content, drilling fluid losses, and any additives used. e) A drilling log which defines and classifies the type of formations encountered during the drilling. The log will consist of the depth at which each change in formation is encountered,the classification of the material encountered, its color and particle size. Classification of silt, sand, gravel, cobbles, etc. shall be based on the size of material encountered in accordance with the established and accepted geologic standard for classification of these materials. If more than one size of material is encountered in a formation such as"sand and clay",an estimate of the quantity of each shall be recorded, such as "20%sand, 80%clay". f)All measurements for depths shall be referenced to the existing ground surface at the well site. 5. During the drilling of the test holes,the Contractor shall collect representative samples of the rotary drill cuttings at 10-foot intervals and at formation changes. The City may direct the Contractor to collect samples at more frequent intervals if deemed appropriate. The samples collected shall not be washed. They shall be carefully drained of excess drilling fluid but in a manner which will preserve the finer particle size of the sample. Each sample taken shall be preserved in quart-size "Zip-Lock" plastic freezer bags and marked as to date,and depth. The samples shall be properly stored by the Contractor in a manner as to prevent breakage or loss until they are accepted by the Engineer. 6. Upon completion of the test hole drilling, a geophysical log shall be conducted. LUHDORFF&SCALMANINI CONSULTING ENGINEERS 11